\Interface Overview
A program's "interface" refers to how the screen appears, and how
the program presents choices to the user. BIG D 6.0 features a
graphical user interface consisting of pull-down menus, dialog
boxes, and viewports. Since it is mouse-driven, the interface
makes it easy to set up camera, lights, and rendering variables.

The majority of BIG D's features can be accessed using the mouse,
but occasionally you have to type in data such as new file names,
coordinates, and light intensities.

The BIG D screen contains a title bar, menu bar, a tools bar,
viewports, and a prompt area.  Pull-down menus appear when you
click the cursor over menu choices on the main menu bar.  When
these choices in turn are picked by clicking with the mouse
button, they bring up dialog boxes which control most BIG D
features.

<SEE ALSO>
Menus
Tools Menu
Keyboard Shortcuts

\Procedure Summary
Here is a quick summary of the steps to follow, to render
with BIG D:

1.  INSTALL, CONFIGURE, AND LOAD BIG D 

You must first install BIG D  on your hard disk and configure BIG
D for your system.  The BIG D installation and setup programs
make this easy: just run INSTALL.EXE and then BDSETUP.EXE.  To
load BIG D, type "BIGD" at the DOS command prompt.

2.  IMPORT THE 3D MODEL

Before working with BIG D you must have a 3D model in
DXF format.  Once BIG D is loaded, you can open a DXF
file of your choice by using the Files menu on the main
menu-bar.  A sample DXF file (named LOGO.DXF) is supplied with
BIG D so that you can begin to use the program
immediately.

3.  ASSIGN MATERIALS

Materials are assigned to objects in the model by layer. 
When you first open the DXF file, each layer in the model is
automatically assigned a material from BIG D's materials
libraries.  Change the materials and texture assignments by
using the Layers and Materials dialog boxes of the Options
menu.  This allows you to assign any material to any layer.
                                                         1-2   

4.  SPECIFY RENDERING OPTIONS
The Options Menu allows you to set variables which control
the appearance and format of the finished rendering, as well
as processing time for the rendering.

5.  DEFINE VIEWS
You must define at least one view by locating both camera
and target.  Together they determine how you will see the
model in the generated image.  This process can be repeated
to generate as many views as you wish.
(Using the viewports, you can fine tune the locations of the
camera and target to get exactly the view you want.)

6.  LOCATE LIGHTS

You must also define at least one light source.  The Lights
Menu allows you to add, delete, and edit lights, and also to
manipulate ambient light and sunlight.  The Add Light dialog
box lets you locate lights in the viewports.

7.  RENDER THE SCENE

Once you have assigned materials, defined lights and views,
and specified rendering options, use the Render Scene option
from the Render menu to create the image file that is the final
product.

BIG D allows you to rapidly create preliminary renderings of
the entire scene, or of selected layers only.  You can check
the results of your choices, and adjust your settings, using
these "rough drafts" before you invest computer processing
time rendering the high quality final image.  The final image
is saved as an image file in the GIF, PCX, or TGA (TARGA)
formats.  The default is GIF.

8.  SHOW THE IMAGE

Use the Show Image option from the Render menu to look at
your finished renderings.

Making Changes

BIG D allows you to easily change any rendering attribute, or
generate additional views.  For example, to change the view,
use the Edit View dialog box.  To lower the light level, use
the Edit Light dialog box.

If you want to make a change in the model itself (such as
moving a chair to the other side of the room) you must make
the change in the modeling program, then reload the updated
DXF file into BIG D.

BIG D remembers all rendering options, lights, views, and
materials from the last session, so you do not have to re-enter
any information.  You do have to generate a new image in
order to see the effects of the changes you have made.  Part
of every rendering is saved and used by BIG D for any sub-
sequent renderings of that scene.  Therefore, many changes
that you might make require only a partial regeneration of the
image file, saving you large amounts of time.  Renderings can be
done quickly at a low resolution to check settings, and then at
high resolution for final, presentation-quality images.

Opening Screen

In the opening screen of the BIG D program, the name and version-
number of the program appear in a title-bar at the top of the
screen.

Below the title-bar are the primary menus of the program,
beginning at the left with the first menu that you will use,
Files, and proceeding roughly in order of use for the others.
                                                       1-7   

BIG D displays the Open Scene dialog box first, because you
usually begin a session by opening a scene.

To the far right of the BIG D screen is the Tools menu, which
provides you with a large and flexible group of viewport
manipulators.  Use this menu to view your model, inside the
program. 

Only the main menu bar and view Tools menu remain fixed.  As
you make menu choices, the screen will change, showing the
appropriate dialog boxes or viewports.

\Mouse
The mouse is a pointing device which controls the screen cursor. 
(The cursor is normally shaped like an arrowhead.)  To operate
BIG D, you must have a Microsoft-compatible mouse, or a
digitizer.  (Most digitizers can be configured to emulate a
mouse.)  Refer to your mouse documentation for instructions on
how to install and activate the mouse - this is usually done by
adding a command to your autoexec.bat file.

NOTE: The mouse must be activated before you start BIG D.  Use
only the "pick button" (usually the left button) for all
operations.

Use the mouse to:

1.  Pick menu items (position the cursor arrow over an item, and
then press the pick button.)

2.  Move "slide bars" to adjust settings, and scroll through
lists (see Dialog Boxes below.)

3.  Drag camera, target, and light icons in the viewports.

4.  Position and pick within a text box before typing in data.

5.  Toggle "buttons" on or off.

When prompted to select an item from the screen, move the cursor
over the item and press the button ("click on" it).  
"Dragging" with the mouse is similar: as you move the cursor, a
rubberband line will extend from the icon to the cursor.  When
you release the pick button, the icon will jump to the new
location.  The new location will show in the Camera coordinates'
text box.

\Menus
BIG D has three menu types: a main menu bar across the top of the
screen, pull-down menus that appear when you pick a main menu
item, and a Tools menu used to set views.

Main Menu Bar

The main menu bar shows all the major program operations.
Clicking on a main menu item activates its pull-down menu.

Pull-Down Menus

Pull-down menus display several related operations. For example,
picking Files from the main menu, activates the Files pull-down
menu. 
<SEE ALSO>
Tools Menu
Ports

\Ports
Before using the Tools menu to adjust views, pick the viewport
you want to manipulate by picking any point within the viewport. 
The name bar at the top of the viewport turns a darker gray,
indicating that the viewport is current. Viewports display wireframe
views of the 3D model.  Use the viewports to graphically locate
icons (for camera, target, and lights) in relation to the model. 

Viewports appear after you load a model using the Files menu
options.  Initially, two ports are displayed; the Top port
displays a top view of the model, and the Front port displays a
front view. 

Viewports can be toggled to fill the entire screen. Use the Fill
Screen button (top right corner of each viewport) to fill the
screen with the current viewport.  Pick the same button again to
shrink the viewport back to its normal size.

A third viewport appears when you add or edit a view (Views menu
option).  The third viewport, in the lower left corner of the
screen, shows how the particular view you're working on will
appear in the rendering. 

The button in the upper left corner of each viewport is used to
change the orientation of the model.  Six alternate view points
are available: Top, Bottom, Left, Right, Front, and Back.  Use
this button like a scroll list; pick the button and hold, move
the cursor over the view you want, and release the pick button. 
Whenever you zoom or pan a viewport, BIG D must redraw the entire
viewport. This is similar to a redraw in AutoCAD.
<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Dialog Boxes
Most of BIG D's features are controlled through dialog boxes,
which appear when you pick options from the pull-down 
menus.  Dialog boxes allow you to input or adjust settings.  
Box Title

Every dialog box has a title in the middle of a blank strip
across its top.  The title describes the purpose of the box.

Labels

Labels describe each element in the dialog box.  The element
described is usually located directly to the right of the label.

Toggle Button

Some dialog boxes contain small square buttons, which appear
adjacent to a single word or phrase of text.  Use the mouse to
click the buttons on or off.  A smaller black square within the
check box means it is active, On.  A blank button is Off.

Text Buttons

A Text Button controls a single function.  Each button is a small
rectangular box, shadowed so as to appear raised and three-
dimensional.  The name of the button's function is displayed on
the button.  Buttons are grouped in sets, and only one button in
a set can be selected at any time.  (For example, [OK] and
[Cancel].)

Use the mouse to select a button.  When a button is selected, it
appears to become depressed, as a 3D button would.
Scroll-List Buttons

Scroll lists appear on the dialog boxes as buttons containing
text (usually a default setting), with labels beside them.  To
change a setting, pick and hold the scroll list button; a list of
alternate settings will appear.  Position over the desired set-
ting, and release to select.

Scroll Boxes

Use Scroll boxes to select one item from a (possibly long) list
of items.  A scroll box consists of a box, titled at the top, a
list of selectable items in a column, and a vertical scroll bar
along the right, with arrowheads pointing up and down.  The
currently selected item in the list is highlighted in dark gray. 
Select items in a scroll list by clicking on their names. If the
number of items in the list exceeds the number of items which can
fit in the box, use the scroll bar down the right side of the box
to scroll through the list.  The up and down arrows scroll the
list one item at a time, with each click of the mouse-cursor on
the up or down arrow.  If you hold down the mouse-button, the
items will scroll continuously.  (You still must pick on the item
before it is selected in the program.)

Slide Bars

Use slide bars to enter whole or decimal numbers within a finite
range.  A slide looks like a scroll bar turned on its side. It
consists of a horizontal bar with left and right arrows at each
end, and a raised square that slides along inside the bar.  This
arrangement allows you to see approximately what range is in
effect for a given type of data.  Beside the slide bar is a
number box, showing the slide bar's current value.  To adjust the
slide bar, pick and hold the small square within the slide bar. 
While holding down the pick button, slide the square back and
forth.  The number box value will change as you slide the square.

Fine tune the slide bar setting with single clicks on the left
and right arrows.  

Text Boxes

Use Text boxes to enter data which cannot be entered by one of
the previous methods, such as numbers and names.  To enter data,
click on the text box, then type the number or text.  It is
necessary to press [Enter] when done.  

Most dialog-box screens come up with the first text box already
active (an active text-box shows white letters on a black
background).  If this is the case, you can enter text without
having to pick the text box.  

If you want to move from one text box to another, without
entering data, use the TAB key.

\Keyboard Shortcuts
Most menu options and some dialog boxes have keyboard shortcuts,
designated by an underlined letter in the menu option.  You may
type the letter to execute the command, and in fact, this is the
quickest way to use the program's menus.

For example, to open a new file using keyboard shortcuts, first
press F to display the Files menu.  Then press O to access the
Open Scene dialog box.  BIG D displays the Open Scene dialog box
just as if you had used the mouse cursor. A keyboard shortcut for
text-boxes is the TAB key, used to step from one to another
without having to enter input.
<SEE ALSO>
Menus
Interface Overview


\Files Menu
The Files menu is your entryway to the BIG D program, since
it is the first menu you see.  It also lets you save your work
during sessions, and exit when you've finished.

If you look through the Files dialog boxes, you'll note they are
similar.  The dialog boxes are, in fact, almost identical (except
for titles), because they concern file management - loading,
merging, and saving files.

When you start a BIG D project you will be working with two
types of files - DXF and BDS.  The 3-D models that BIG D
renders have to be imported in DXF format.  Think of the DXF file
as a model that you hired from a modeling agency;  the DXF file
walks into your "studio" from somewhere else.  Your "studio" is
the BDS file; it contains the environment for the model - camera,
lights, rendering variables.

A photographer does not call in carpenters to construct a new
studio every time he wants to set up a different lighting and
camera arrangement, but simply changes the setup in an
existing studio.  Likewise, you do not "build from scratch" a
new BDS scene for each rendering; you load an existing (or
"seed") BDS file, assign it a name, and then change lights,
camera, and rendering variables.  BIG D files include an
"empty" seed scene with default settings, named BIGD.BDS. 

If you modify BIGD.BDS, you're creating a new prototype
scene-file (copy the original to a floppy for safekeeping).
Three of the six options on the Files menu are used to load
files: New Scene, Open Scene, and Open DXF.  The reason
for all these loading options is that BIG D is designed with the
assumption that you will take more than one work session to
complete most renderings.  By using slightly different proce-
dures - depending on whether you're beginning a new
project, or returning to work on a project - each path is made
more efficient.

Use the other three menu options, Save Scene as, Save Scene,
and Quit, to save your work and exit the program. 

<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as

\Files Summary
Use the Files menu to load files, save your work, and quit at
the end of a rendering session.

Start a project with the New Scene option, using the New
Scene DXF File dialog box to load a model, and then the New
Scene BDS File dialog box to load a BDS scene file.  Load a
scene file by either assigning a new name to the default
BIGD.BDS file, or by choosing an existing scene file from the
scroll box.
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as

\New Scene Procedure
Load a New Model and a New Scene Using [New Scene]

1.  Pick [Files] from the main menu bar and [New Scene]
from the pull-down menu.

NOTE: If you just fired up BIG D, the Open Scene dialog box
will be on the screen.  Pick [Cancel] to clear the screen.

2.  When you pick [New Scene], the [New Scene DXF file]
dialog box will appear.  Use the Directory scroll box if you
need to change directories, and the Files scroll box to pick a
DXF file (ex. condo.DXF).

ANOTHER NOTE: When you have accumulated a large
number of DXF files, it is usually quicker to pick the text box
labeled "Name:" and type in the file name, rather than scroll
through a long list.

3.  Pick the [OK] button.  The New Scene DXF File dialog
box disappears and the New Scene BDS File dialog box
appears.

4.  On the New Scene BDS File dialog box, pick the "Name:"
text box and type in a new name (ex. condsite.BDS).
ONE MORE NOTE: This operation creates a new scene file
from the prototype BIGD.BDS scene file, leaving BIGD.BDS
intact.  The new scene file, condsite.BDS, will now be on the
Files scroll box list. 

5.  Pick [OK] to return to the main menu bar. 
THE LAST NOTE: The DXF file condo.DXF and the BDS
file BIGD.BDS are now linked in a scene/model file named
condsite.BDS.

6.  Pick [Files] from the main menu bar, and [Save Scene]
from the pull-down menu, just to be safe.
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as

\Open Scene Procedure
Load an Existing Scene:

Once you have linked a BDS scene file and a DXF model file,
start your next rendering session by using [Open Scene] to load
the scene/model combination in one process.

1.  Pick [Files] from the main menu bar, and [Open Scene]
from the pull-down menu. (If you just accessed BIG D, Open
Scene will already be on the screen.)

2.  Use the Directories scroll box if you need to change
directories, and pick the BDS file you want from the Files
scroll box.

3.  Pick the [OK] button.
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as


\Open DXF Procedure
Load a Model into a Scene:

This option is useful if you wish to render several models,
using the same scene settings (for example, a series of render-
ings showing a building in various stages of construction.)

1.  Load a BDS scene file using [Open Scene].  The scene file may
or may not contain a model.

2.  Pick [Files] from the main menu bar and [Open DXF]
from the pull-down menu.

3.  Use the Directories and Files scroll boxes to select a DXF
file.

4.  Pick the [OK] button.

5.  Use the [Save Scene as] option so that you don't destroy the
original scene file.

Using [Save Scene as] To Assign a New File Name

1.  Pick [Files] from the main menu, and [Save Scene as]
from the pull-down menu.

2.  The [Save Scene as] dialog box will show the last file you
just loaded as the current scene.  Pick the "Name:" text box,
type in a new name, and then press [Enter] to assign the new
name. 

3.  Pick the [OK] button to clear the screen.  You have now
created a new file, and the original BDS file will remain intact.

<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as


\Save Scene Procedure
Use this option periodically during your work sessions (say,
every twenty minutes to an hour), and before you quit, to save
the current scene and its settings.

1.  Pick [Files] from the main menu bar, and [Save Scene]
from the pull-down menu. 

\Quit Procedure
1.  When you're through, pick [Files] from the main menu bar,
and [Quit] from the pull-down menu.  (Or type "F" and then
"Q", as keyboard alternatives to use of your mouse.)

2.  If you have made any changes after the last time you used
[Save Scene], BIG D will ask if you want to save the changes. 
Pick [Yes] if your session went well, [No] if not. 
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as


\New Scene
Picking [New Scene] from the Files menu calls up the New
scene DXF File dialog box, and then the New Scene BDS File
dialog box. 

New Scene DXF File lists all the 3-D models saved in DXF
format in your system.  The DXF stands for Drawing Inter-
change File format.  This file format was initially developed by
AutoCAD.  The DXF format is now used by virtually all 3-D
modeling programs.  BIG D imports DXF files from any
source. 

The Directories scroll box lists the directories in your system
that contain DXF files.  The name of the current directory
appears by the label "Directory."  The Files scroll box lists all
the DXF files in the current directory.  If you cannot find the
name of the DXF file you want in the Files scroll box, you
may need to change directories by picking another directory in
the Directories scroll box.

When you pick a DXF file, the file name will appear in the
text box labeled "Name:" at the top of the dialog box.

NOTE:  Selecting a DXF file to use in BIG D does not in any
way change the original drawing model or the DXF file (as if
the modeling agency didn't actually send over the top model
you asked for, but an amazingly life-like clone).

As with all BIG D dialog boxes, picking [OK] implements
whatever changes you made using the dialog box (in this case
loading a DXF model), and picking [Cancel] aborts any of
your operations.

When you pick [OK] the New Scene DXF File dialog box is
replaced by the New Scene BDS File dialog box, so that you
can load a scene around your model.
There are two ways to load a scene with New Scene:

1.  Pick the text box labeled "Name:" and type in a new name
to load the bigd.bds prototype scene file.  This scene file is an
"empty studio"; it has no lights or views defined.  Using this
route leaves the original bigd.bds scene file intact.  The new
name will appear on the Files scroll list.

2.  Pick a BDS file from the Files scroll box.  This BDS file
may or may not contain a DXF model.  If it does, the DXF
file you just selected will "kick out" the previous model and
take its place. 

If you pick a BDS file from the scroll box, use [Save Scene
as] to create a new file for the scene/model combination, and
leave the original BDS file intact.  [Save Scene as] will
prompt you for a new file name.  If you save the new scene/-
model combination with [Save Scene], it will overwrite the
original BDS file.

Picking a BDS file from the Files scroll box brings in the file
with all its lights, camera, and rendering variables intact,
which is the reason to use this procedure rather than the simpler
one of using the bigd.bds prototype file.

Use New Scene if you want to do a series of renderings of the
same model with different scene settings, such as a walk-
through, or lighting studies of the same architectural model
through the course of a day.  
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as

\Open Scene
Use Open Scene for follow-up sessions on a rendering.  The
Open Scene dialog box allows you to load an existing scene/-
model combination (BDS file and DXF file that have been
linked in the BDS scene file) in one step.  When you first load
BIG D, the screen appears with the Open Scene dialog box
already in place, since it is usually the first option you need. 

You can also use Open Scene to load a BDS scene first, and
then load a DXF model into it.  (As if you had your studio all
set up and the model came in late, complaining about traffic.)

When you load BIG D, the screen appears with the Open
Scene dialog box already in place. The most efficient use for
Open Scene is to load a scene/model BDS file that you created
using New Scene. Simply pick the BDS file name from the Files
scroll box. Several of BIG D's main menu choices are disabled
until a scene is loaded; even if you just want to play around
with lights or views, you have to load a scene first.

BIG D includes several sample scene files on your distribution
disks - bigd.bds, logo.bds, house.bds.  All except bigd.bds
include a DXF model, so that you can begin to use BIG D
immediately.

To load a BDS file using Open Scene, you MUST pick an
entry on the Files scroll list.  The program will not allow you
to pick the "Name:" space and type in a file name that 
doesn't already appear on the list.  You must select an existing
file and change the name using [Save Scene as] to create a
new scene file.
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as

\Open DXF
This option is useful if you want to produce a series of ren-
derings of different models using the same scene settings -
similar to a photographer who's set up a backdrop, lights, and
camera in a supermarket, and is pulling a line of kids one by
one into the model's seat.  Use Open Scene to load a scene,
and Open DXF to load a model.  Manipulate camera, lights,
etc. until they're right, then use Open DXF to transfer different
models into the scene one after another.

Use Open DXF to load a model into a scene.  Once the model is
loaded, the combined scene/model file retains the BDS extension,
although the model is still listed with a DXF extension in the
DXF Files scroll boxes.  
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as

\Save Scene as
"Save Scene" and "Save Scene as" are used to save your work
during asession.  When you have loaded a BDS file with Open
Scene, and a DXF file with Open DXF, call up [Save Scene as] and
type in a new file name.  Otherwise you will write over and
destroy the original BDS file.

Once you have created the new BDS file, and used [Save
Scene as] to save it under its new name, you can use [Save
Scene] thereafter, without fear of writing over the default or
"seed" BDS file.

You can also use Open Scene (in combination with Open
DXF) to load a scene and then load a model - useful if you
want to render a series of DXF models using the same scene
settings.  Each DXF model that you load will "kick out" the
previous model.

Any time you load a BDS file (with or without a model) to
work on, but want to leave the original BDS file intact, you
must - at some point - assign a new name to the file. 
Otherwise, your changes will write over the original BDS file. 
If you have not already typed in a new name, using the New
Scene option, use [Save Scene as] to assign a new name.

When you pick [Save Scene as] from the pull-down menu, the
last BDS file you loaded will be the current file.  Pick the
"Name:" text box, type in a new name, and press [Enter] to
"split off" the new BDS file from the original BDS file.  Both
old and new filenames will show in the Files scroll boxes.
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as

\Save Scene
Save Scene simply saves the current scene file - with or
without a DXF model.  The Save Scene option does not call
up a dialog box; all you have to do is pick it on the pull-down
menu.  It's a good idea to use Save Scene periodically during
a work session, particularly when you have just finished a
major portion of the job, such as defining all the lights, or
assigning materials.
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as


\Quit
The Quit option exits BIG D.  If you have made any changes
since the last time you used [Save Scene] or [Save Scene as],
picking [Quit] prompts you to save.  Otherwise, no dialog box
appears.

Alternatively, use the Open Scene option to load an existing
BDS file, the Open DXF option to load a model, and then save
the combination with a new file name.

If you have already linked the scene and model file into a BDS
file, use Open Scene to call up the combination file.
Use [Save Scene as] to assign a new name to a file and save
it.  Otherwise, use [Save Scene]....and use [Quit] to quit.

In any case, you should save copies of all the .BDS sample
scene files that come with the BIG D program, either in a
deep, dark subdirectory of your hard disk, or on a dark floppy
disk deep in your collection of back-up disks. (You do have
such a collection, don't you?)  That way, you will always have
the prototype scene-descriptions available to you.
<SEE ALSO>
Files Menu
New Scene
New Scene Procedure
Open DXF
Open DXF Procedure
Open Scene
Open Scene Procedure
Quit
Quit Procedure
Save Scene
Save Scene Procedure
Save Scene as
\Options Menu
The Options menu has five headings: Layers, Image File, Expert,
Display, and Materials. This broad range of operations requires
two chapters.

Layers and Materials dialog boxes are used to assign materials
and textures to your model.  Although Layers and Materials are at
opposite ends of the Options menu, they work together in the
creation of renderings.

<SEE ALSO>
Options Menu
Angular Snap
Angular Units
Colorspace
Display Dialog Box
Display Dialog Procedures
Linear Snap
Linear Units
Bucket Size
Erase Rendering File
Expert Dialog Box
Expert Dialog Procedures
File Compression
Generate Bump Map
Ray Depth
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel
Change Library Button
Layers Dialog Box
Open Library Dialog Box
Add New Library
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflectiont
Bumping a Texture Map
Can Be Shadowed

\Materials Procedure
The route you choose for material operations depends on
whether you want to assign an existing material, edit an
existing material, or create a new material.  The routes
are somewhat artificially separated; you will probably use
several for any particular rendering.

Assign Existing Material

1.  Pick [Options] from the main menu, and then [Layers]. 

2.  The top scroll box on the Layers dialog box contains On
buttons for each layer, layer names, the name of the default
materials, and the material libraries.  Make sure that the layers
you want to use in the rendering are toggled "ON" (the button
is black if the layer is On).

3-A.  If the material you wish to assign is in the current
library (listed in the Materials scroll box), pick the material
name in the scroll box, and it will highlight.

3-B.  If you want to use a material from another library, pick
the [Change Library] button to call up the Open Library
dialog box, which contains a Files scroll list of BIG D's
libraries.  Pick the library you want, and then pick [OK]. 
When you return to the Layers dialog box, the new library
name appears by the label "Current Library", and its contents
are listed in the Materials scroll box.  Pick the material you
want.

NOTE:  If you need to access library files from elsewhere in
your system, use the Directories scroll box on the Open
Library dialog box to change directories.  Position the cursor
over the drive you want and rapidly click twice.  Double click
your way to the directory you need.

4.  Once you have chosen the current material, pick the layer
(or layers) you want in the Layers scroll box.  The line will
highlight.  

5.  Pick the [Apply] button, or double-click on the layer, to
actually assign the material.

6.  Follow the same procedure - pick a material, then a layer,
then [Apply] - to assign materials to the remaining layers.

7.  When you've finished, pick the [OK] button to return to
the main menu.  (Or [Cancel] if you change your mind.)

NOTE:  If you used a material that has a texture map assigned
to it, see the Edit Texture Usage section.

Edit a Material

Use this route to change the settings of a material in BIG D's
libraries.

1.  Pick [Options] from the main menu, and [Materials] from
the pull-down menu, to call up the Materials dialog box.

2.  First, select the material you want to edit.  If it's in the
current library (listed in the Materials scroll box), all you
have to do is pick it.  If you need to change libraries, pick the
[Change Library] button in the Library Operations group box 
to change libraries.

3.  Once you have selected the material, it will be listed beside
the label "Current Material" and its library will be listed as
the "Current Library".  Pick the [Properties] button in the "Edit
Material" group box. 

4.  The "Material Properties - (Material Name)" dialog box
contains settings for all of the current material's properties. 
Adjust the settings for Color, Coefficients, and Options.  Pick
the [OK] button if the new settings are, indeed, OK.

5.  You will return to the Materials dialog box, and the
changed settings will be incorporated into the material.  If you
want to check your adjustments, pick the [Show Material]
button in the Edit Material group box.  BIG D will generate a
quick rendering of a sphere.  The edited material is assigned
to the sphere.  Press any key to get out of the Show Material
mode.

6.  To use the newly edited material, access the Layers dialog
box assign it to a layer.
<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Add or Delete a Material
Use this route to create a new material while leaving the base
material intact.

1.  Pick [Options] from the main menu, and [Materials] from
the pull-down menu.

2.  You can use any of BIG D's materials for the base mate-
rial, but the closer the original material is to what you want,
the fewer changes you will have to make.  The new material
will be in the same library as the base material.  Select a base
material from the Materials scroll box; the base material will
appear at the Current Material label, and its library at the
Current Library label.  

3.  In the "Material Operations" group box, pick [Add New
Material] to access the "Material Properties - New Material"
dialog box.  

NOTE:  If you want to delete the current material, at this point
pick [Delete Material] from the Material Operations box.

4.  When you pick [Add New Material], the "Material Prop-
erties - New Material" dialog box appears.  The dialog box comes
up with settings for the base material.  Type in a new name for
the material (it will appear in the "Name:" text box), and press
[Enter].  This creates a new material and leaves the original
material intact. 

NOTE:  If the new material you're creating has a texture map,
at this point, pick [OK] to return to the Materials dialog box. 
In the Edit Material group box, pick the [Texture] button to
access the Material Texture dialog box, so that you can edit the
Map Attributes.

5.  Specify new settings for Color, Coefficients, and Options,
as needed.

6.  Pick the [OK] button to return to the Materials dialog box. 
Pick the [Show Material] button in the "Edit Material" group
box to get a look at your creation.

7.  The new material name will now appear on the scroll list
of materials, in the same library as the base material.

8.  To use the new material, go to the Layers dialog box and
assign the material to a layer.

Difference Between Editing and Adding a Material

To summarize the difference between editing and adding a
material:

EDIT MATERIAL.  Go to the Materials dialog box and pick
the [Properties] button from the Edit Material group box to
access the "Material Properties" dialog box.  This route will
change the settings of the original material.  

ADD MATERIAL.  Go to the Materials dialog box and pick 
the [Add New Material] button in the Material Operations
group box to access the "Material Properties - New Material"
dialog box.  This route will define a new material which will
be added to the same library as the base material, and will
leave the base material settings intact.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Textures 
In addition to the texture maps furnished by BIG D, a texture
map file may be captured with a video camera, scanned with
a scanner, or created with a paint program, as long as its file
format is one that BIG D recognizes.

The settings for color do not affect textures, but all other
material properties do.  You cannot adjust the color of "brick-
red" to make it "brick-purple."  You CAN adjust the coeffi-
cients to make "shiny brick-red," for example, by raising the
                                                         3-5   
Specular Reflectivity Coefficient.  You can also adjust the
scale, angle, and repeat mode of the texture.  For example, you
can make "brick-red" into "big brick-red," or "skinny Roman
brick-red."  

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Edit Texture procedure
Use this procedure to "wallpaper" an object in your model with
a texture map.

1.  Pick [Options] from the main menu, and [Materials].

2.  The materials furnished by BIG D that have texture maps
assigned to them are all in the bigd.bdm library.  If bigd.bdm
is not the current library, pick [Change Library] to call up the
Open Library dialog box to make bigd.bdm the current
library.

3.  Pick the material you want to edit (for example, "brick-
red") from the Materials scroll box.  Its name will appear
beside the label "Current Material:".

4.  Pick the [Texture] button in the Edit Material group box
to get to the Material Texture dialog box; the title strip will
read  "Material Texture - brick red."

5.  In the Files scroll box, pick the texture brckred.gif, which
will then appear in the text box labeled "Name:".

6.  Specify the Map Attributes: 

a. Set "Repeat" to Normal or Reflect.

b. Set "Width" and "Height" to the scale you want.

c. Leave "Rotation" at zero unless you want to tilt the texture
map.

d. Leave "Antialiasing" at its default of 0.5.

e. Toggle off "Black pixels invisible." 

7.  Pick [OK] to return to the Materials dialog box.

8.  Go to the Material Properties dialog box to adjust the
coefficients, if you need to.

9.  Pick the [OK] button on the Materials dialog box to return
to the main menu, and change the original texture.  It can be
assigned using the Layers dialog box.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Single Unit Texture Procedure
You can use a texture map, such as a painting, tree, or human
figure, as a single-unit "prop" ("entourage" for all you archi-
tects) in your rendering.  To use a texture map in this manner,
you must construct a plane, or "mounting board" in your 3-D
model, place it on a separate layer, and then map the texture
to the mounting board.  

1.  First, you must decide on the View you want to use, so that
you can place the mounting board in the model perpendicular, or
nearly so, to the line of sight.

2.  Get out of BIG D and into your modeling program.  Even
though single unit textures may have irregular edges, they are
each contained within a square, and the Width and Height of
the texture map refer to the size of this bounding square.  You
must construct the mounting board in a size that makes sense
relative to the scale of your model, and then "scale up" 
the texture map to fit the mounting board.  For example, to
place a medium-size tree in your model, create a mounting
board 20 feet by 20 feet.

3.  Set up a layer for the texture mounting board.  Draw the
board and position it in the model.  Make sure to draw the
mounting board with the lower left corner at the origin of the
coordinate system.

4.  Save your model, including the new mounting board, as a
DXF file.  Load the DXF file into BIG D (see the Files
chapter).  The mounting board layer will now appear on the
Layers dialog box scroll list.

5.  Specify the texture map you want to use (in this example,
tree.gif) as the Current Texture, using the procedure described
in steps 1-5 of the "Edit Texture" section of Help.

6.  On the Material Texture dialog box, set Repeat to Off,
Rotation to zero, and leave Antialiasing at the .5 default.

7.  Set the Map Width and Height to match the size of the
mounting board.  In the tree example, if your Linear Units
are inches, set Width and Height to 240 (20'X 12").

8.  Toggle "Black pixels invisible" to On.  The area of the
texture's bounding square not covered with the image is
assigned black pixels.  The On setting, therefore, will make the
part of the mounting board not covered with the image
disappear.
NOTE:  If you create your own texture map to use as a prop,
make sure that the background is pure black.  Only a pure
black pixel (color settings of 0, 0, 0 in either HSV or RGB)
will disappear.

10.  Pick [OK] to exit the Material Texture dialog box.

11.  Assign the texture to the new "mounting board" layer by
using the Layers dialog box.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Create a Bump Map Procedure
1.  Create a model of the surface using your 3D modeling
software.  If you intend to have the surface repeat (like wall-
paper), set up the surface model as a square with opposite
sides matching.  

Example:  Create a square 6" on a side with
a 1/2" diameter sphere embedded at the center of the square.
Create the model so that the center of the sphere and the 
center of the square coincide with the origin of the coordinate
system.

2.  Export the model as a DXF file (DXFOUT command in
AutoCAD).

3.  Load BIG D and press [Esc] to get rid of the Open Scene
dialog box.  Select [Files] and then [New Scene].  Select the
DXF file you just created (ex. BUMP.DXF).  Enter a new
scene name or accept the default new scene name (same as the
DXF file name).  Pick the [OK] button.

4.  The resolution will affect the window of the new view, so
set resolution first.  Select [Options] from the main menu, and
[Image File] from the pull-down menu.  Set the resolution for
the bump map (ex. 320 X 200) and toggle Fast Shade off. 
Leave [Samples per pixel] set to 1, [Grid size] at 4, and set
[Dithering] to 0.  Pick [OK] to exit the dialog box.

5.  Select [Views] from the main menu.  Enter a view name -
"bump," for example.  Remember that the view name will be
the name of the bump map image file.

Set up a top view of the bump map surface.  Pick the lower
left viewport, and then the button in the upper left corner of
the viewport.  Scroll and select the "Top" option.  Use the
Zoom button (inward or outward pointing arrows on the Tools
menu) to zoom the port so that the edges of the map do not
show within the viewport.  Set Parallel projection, and then
pick [OK] to exit the View dialog box.

6.  Select [Options] and then [Expert] to call up the Expert
dialog box.  Toggle the [Generate bump map] button On,
then pick the [OK] button.

7.  Render the bump map image: select Render from the main
menu, and then [Render scenes] from the pull-down.  Pick the
[Render] button to generate the image file.
NOTE: because you toggled on [Generate bump map] the file
will be a "greyscale" image file with a GIF extension.  The
image file will be saved in the same directory as the scene file 
(if you accepted the defaults during installation, the directory
will be \BIGD6).

8.  Once the rendering is complete, press any key to return to
the Show Image dialog box.  Pick [Cancel] to exit the box. 
Pick [Options], then [Expert], and toggle off the [Generate
bump map] button.

NOTE:  Be sure to toggle off the [Generate bump map]
button unless you are rendering a series of greyscale image
files.  If you forget to do this, all subsequent renderings will
be greyscale renderings instead of color renderings.

9.  You can now assign the greyscale image file to a material.

a.  Select [Options] from the main menu, and [Materials]
from the pull-down menu.

b.  Position on a base material using the Materials scroll list. 
The base material can be a color or a texture.  The bump map
will take on the color, and other material properties, of the
base material.  Ex.  Position on "blue."

c.  Pick the Add New Material button and type in a new
material name (ex. BUMP).  Pick [OK] to exit the Material
Properties - New Material dialog box.

d.  In the Edit Material group box, select the [Bump] button
to call up the Material Bump dialog box.

e.  Use the Directory scroll list to locate the bump map image
file, which will be in the same directory as the scene file, such
as \BIGD6.

f.  Select the image file from the Files scroll box.  (In our 
example, BUMP.GIF.)

g.  Set the Repeat mode to Normal, so that the bumps will be
repeated in all directions.  Adjust the map Width and Height,
and Max Elevation, to produce a reasonable size relative to the
model.
                                                         3-9   
h.  Pick the [OK] button to exit the Material Bump dialog box. 
You now have a new material consisting of a bump map and
the color blue.  (In this example, a blue surface with an array
of spherical bumps.)  The new material will be listed in the
same library as the base material.

i.  Use the [Show Material] button for a quick preview of the
newly-created, bump-mapped material.

NOTE:  See "Bump Maps" in the Options section of this
chapter for more about bump map procedures.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Layers Dialog Box
You will use the Layers dialog box to assign a material to each
layer of your three-dimensional model.  If you use only the
materials supplied by BIG D, you need only the Layers box.

Layers Scroll Box

At the top of the Layers dialog box is a scroll box with the
headings "On", "Layers", "Material", and "Library".  
The boxes under "On" are used to toggle each layer on or off. 
A black dot in a box indicates that the layer is On, and will be
rendered.  In order to save rendering time, you may wish to
turn off all but one or two layers while you are experimenting
with materials, lights, and views.  You may also want to turn
off a construction layer, or other layers extraneous to the final
rendering.

The original entries under "Material" and "Library" are default
materials (and their libraries) assigned by BIG D. 

<SEE ALSO>
Change Library Button
Layers Dialog Box
Open Library Dialog Box
Add New Library

\Change Library Button
BIG D has eight Materials libraries.  The default library is
bigd.bds, which contains materials with texture maps, plus
various colors.  The other seven libraries each contain the
same 71 colors, but each library has different Material Proper-
ties settings - for bright, dark, matte, reflective, reflective-
transparent, shiny, and transparent.  So you have over 500
materials to play with before you even begin to edit and add.
Use the [Change Library] button to call up the Open Library
dialog box.

<SEE ALSO>
Change Library Button
Layers Dialog Box
Open Library Dialog Box
Add New Library
Change Library Button
Layers Dialog Box
Open Library Dialog Box
Add New Library

\Open Library Dialog Box
At the top of the Open Library dialog box are three labels:
"Name:" contains the file name of the current Materials library,
"Directory" shows the directory path for the library, and
"Filter" shows the file extension of all its files.

Below the labels are scroll boxes for library Files and Directo-
ries.  Use the Files scroll box to select another of BIG D's
Materials Libraries from the BIG D directory.  If you have
Materials files in other directories, use the Directories scroll
box to change to that directory.  

<SEE ALSO>
Change Library Button
Layers Dialog Box
Open Library Dialog Box
Add New Library

\Materials Scroll Box
The Materials scroll box on the Layers or materials dialog boxes
lists the individual materials in the current library.  The
current material is highlighted, and its name and library appear
at the Current Library and Current Material labels.

Apply Button

The [Apply] button, on the Layers dialog box, is disabled until
you select a current material and a current layer.  When you pick
the [Apply] button (or double-click on the layer's line), the
material is assigned in the Layers scroll box.

<SEE ALSO>
Change Library Button
Layers Dialog Box
Open Library Dialog Box
Add New Library

\Materials Dialog Box
The Materials dialog box is the waystation to BIG D's material
editing capabilities.  From the Materials dialog box, you can
access Material Properties, Material Texture, and Material
Bump dialog boxes to add, edit, and delete materials.

The Material Properties dialog box contains settings for a
material's Color, Ambient Reflectivity, Diffuse Reflectivity,
Specular Reflectivity, Mirror Coefficient, Transparency,
Smoothness, Noise Coefficient, and Refraction Index.  You can
also specify each material's internal reflectivity, metallic
reflectivity, ability to cast shadows, and to be shadowed.

You may use the Material Texture dialog box to assign a
texture map, in the form of a file, to any of BIG D's materials. 
As well as the texture maps supplied with the program, BIG D
can import texture maps from other sources.  

The Material Bump dialog is used to assign a bump map to a
material, and to adjust the bump map settings.
The Layers dialog box controls which material is assigned to
which layer.  The layers used in BIG D are the same as the layers
specified in your 3D model.

If your model shows the same material on different layers, you
can specify the same material for all the layers in one opera-
tion.

For example, if you are doing a rendering of a stucco house
with a 3-foot high stucco garden wall, and the house walls and
garden wall are on different layers, simply pick the house wall
layer and the garden wall layer when you are assigning the
material "stucco."

However, if you change any of the properties of a material,
such as color or diffuse reflectivity, rename the changed
material as a new material, and put the objects to which you
assign it on a different layer.

For the project described above, suppose the stucco garden
wall has pilasters every 12 feet, and you wish (in a lapse of
taste) to show the pilasters in a darker stucco than the main
part of the garden wall.  If so, you must create a new, darker
stucco, put the pilasters on a separate layer, and assign the
darker stucco to the pilaster layer only.

The Materials dialog box is a waystation to the
various materials operations.  It contains labels for Current
Material and Library, a Materials scroll box, and three group
boxes: - Edit Material, Material Operations, and Library
Operations. You must select a material in this scroll box to make
any changes to the material in the other dialog boxes.  

Edit Material Group Box

The Edit Material group box, on the Materials dialog box,
contains the buttons [Properties], [Texture], and [Bump], which
access dialog boxes used to change the settings of existing
materials.  Each of these dialog boxes is described below.
Show Material

The [Show Material] button, on the Materials dialog box, lets you
get a quick look at the Current material.  [Show Material]
generates a simple scene that consists of a sphere sitting on a
checkerboard, with a blue background.  The Current material is
assigned to the sphere, which shows all the material properties,
including textures and bumps.

When you pick [Show Material], the Show Material dialog
box appears, which controls settings for Sphere diameter and
Resolution.  The default for Sphere diameter is 1, but if you
want to look at a texture, set Sphere diameter large enough to
see the texture adequately.  For example, if you want to see a
brick pattern, set Sphere diameter to 50 so that you can see
several courses of 8" brick.

The default size for Resolution is 50 X 50 pixels.  Higher
resolutions increase rendering time slightly, but more details
are visible in the rendering.  In the example above, you should
set Resolution to at least 200 X 200.  Press any key to exit
[Show Material], and return to the Materials dialog box.

NOTE: [Show Material] creates a new image file (showmat.-
gif), and erases the previous one, each time you use it.  Ad-
vanced users may use a text-editor to look at, or change, the
default settings (checkerboard and background, lights, vari-
ables, etc.) in the showmat.bds file, in the "showmat" subdi-
rectory.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Material Operations
The Material Operations group box, on the Materials dialog box,
contains the buttons [Add New Material], [Delete Material], and
[Copy Material].  If you wish to create a new material, first
select the base material from the Materials scroll box, and then
pick [Add New Material] to access the "Material Properties - New
Material" dialog box.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Delete Material
If you wish to delete a material from a library, select the
material to be deleted from the scroll box, and pick [Delete
Material] on the Materials dialog box.  A screen comes up that
asks, "Are you sure you want to delete this material?"  Pick the
[Yes] or [No] button.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed
\Copy Material
This option, on the Materials dialog box, is used to copy a
material from one library to another.  Position on the material
you want to copy, then pick the [Copy Material] button.  The Copy
Material dialog box will appear, allowing you to select a library
name (from the Files scroll box), or to specify a new
drive/directory.  Pick the [OK] button to complete the Copy
Material operation.

NOTE: If the material you are copying already exists in the
target library, you will be asked if you want to overwrite or
replace the existing material.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Add New Library
Use this option, on the Materials dialog box, to create a new
"empty" library.  The newly created library can then be filled
with materials using the [Copy Material] option.  

Select the [Add New Library] button.  Enter the new library
name and the drive/directory.  If a library already exists
with the same name, you will be asked if you want to replace
the existing library with the new library.  Normally, you would
not replace an existing library with a new empty library.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Copy Library
The Copy Library option, on the Materials dialog box,  is used to
copy an existing library to a new drive or directory.  Use this
option to back up your libraries to floppy disk, or to make a
copy of a library in a different subdirectory.

Use the [Change Library] button to select the library you
wish to copy, then select the [Copy Library] button.  The
Copy Library dialog box will appear allowing you to specify
a new library name and drive/directory.
NOTE: If the library already exists on the target drive/direc-
tory, you will be asked if you want to replace the existing
library.
<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Material Properties Dialog Boxes
The "Material Properties- New Material" and the "Material
Properties - (Material Name)" dialog boxes are identical except
for titles, and the "Name:" text box used for new materials. 
Both boxes contain group boxes labeled "Color", "Coefficients",
and "Options."

The dialog boxes Material Properties - New Material, and Material
Properties - (material name) will come up with the settings for
the current material in the Material dialog box.  If you are
using the Material Properties - New Material dialog box to create
a new material, type in a different name so that the base
material will remain intact, and press [Enter].  

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\HSV Model
The HSV-based model (Hue, Saturation, Value) is easier to use
than the RGB model because you can specify a hue separately,
and then lighten or darken it.  The RGB model (Red, Green,
Blue) is a closer analog of the actual physics of color mixing
in a CRT. 

The traditional HSV color model defines Saturation as the
purity or vividness of a color, measured on a scale from 0 to
1.  A pure color is 100 percent saturated, and is designated as
1.00.  Zero saturation results in no color at all, a shade of
gray or white.  Value refers to the lightness or darkness of a
material, regardless of its saturation.

BIG D has made the traditional HSV color model much easier
to manipulate by using the Saturation slide bar to add white to
a hue, and the Value slide bar to add black to the hue.

Move the Saturation and Value slide bars all the way to 1.00, and
change hues by adjusting the Hue slide bar.  This brings up pure
spectral hues in the color patch. If you want a lighter color,
move only the Saturation slide bar to the left.  If you want a
darker color, move only the Value slide bar to the left.  If you
wish to make the color more gray, move both slide bars to the
left.

<SEE ALSO>
Color

\RGB Model
A computer produces color on the CRT by mixing colored
light.  (Actually an "electron gun" activates tiny dots of phos-
phors on the screen, which produce primary colors, and then
your eye mixes them.) Primary hues, both in light and pigment,
are those which can be mixed to produce almost all other hues.  

Traditional pigment primary hues are red, yellow, and blue. 
Primary hues of colored light approximate, but do not match
exactly, the peak spectrum wavelengths of red, green, and blue
light.  These three wavelengths can be mixed in various
proportions to match the range of hues that we can see.
This can be confusing if you are accustomed to mixing pig-
ments.  For example, mixing red and green pigment usually
produces sludge-gray pigment.  However, mixing red and
green light produces yellow light, because red and green light
are primaries, and yellow lies between them in the spectrum. 
(If, deep down, you don't believe this, get close to your TV
screen and squint at a yellow area, such as Big Bird.  You'll
see little red and green dots that make up the yellow.)

Adding more primary color to a pigment mixture tends to
darken the resulting color, whereas increasing the amount of
red, green and blue in a mixture of light brightens the resulting
color toward white, because you are increasing the total
amount of light.

If you have specified an RGB color model, moving the R, G,
and B slide bars to the far right produces white - the maxi-
mum amount of light.  Move all three slide bars to the left to
produce black, or no light.  Subtract blue and green from the
white mixture to produce red.  Slowly move the red slide bar
to the left to darken the color. Subtract green from the white
mixture to produce violet.  To create the other colors, a few
experiments like the above are all that is needed.

<SEE ALSO>
Color

\Coefficients
The coefficients, on the Materials Properties dialog box,
fine-tune the way a material reflects or transmits light.  Before
you start changing settings closely associated with brightness
values, check the brightness knob on your CRT.

\Ambient Reflection Coefficient
Ambient Reflection Coefficient determines how much Ambient
Light a particular material will reflect, and thus determines
how light or dark a material will be when it is shaded from other
light.  If there were no Ambient Light and Ambient Reflection
in a rendering, surfaces not illuminated by other lights would
appear solid black.

The Ambient Reflection Coefficient does not affect how much
light a material reflects from point, spot, and directional
lights, only from Ambient light.

Use the Ambient slide bar/text box on the Material Properties
dialog box to set the percentage of Ambient light that a mate-
rial reflects.  Typical values range from 0.10 to 0.20.  

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Diffuse Reflection Coefficient
Diffuse reflection is light that is reflected from a matte, or
rough, surface.  The small surface irregularities bounce the
light back in all directions, making a diffuse reflection look
soft-edged and spread out.

The amount of diffuse reflection from any specific plane of an
object depends on the orientation of that plane toward each
light.  The more a surface faces a light, the more light is
diffusely reflected, and the brighter the surface will be.  
Examples of surfaces which produce primarily diffuse reflec-
tions are fabric, stucco, brick, newsprint, and concrete. 

The ratio of diffuse reflection to specular reflection 
cues the eye to how rough or shiny a surface is.  A matte
surface typically has a Diffuse Coefficient of about 0.80.  A
mirror may have a diffuse coefficient of only 0.10, but a high
specular reflection coefficient.

The Diffuse slide bar/text box governs the amount of light a
material reflects diffusely.  All the lights in a rendering con-
tribute to the light available to be diffusely reflected.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Specular Reflection
Specular reflection is produced by light striking a shiny sur-
face; because the surface is smooth, the light is reflected in
one direction.  Highly specular materials such as metal will
exhibit shiny, concentrated highlights.

Typical Specular reflection coefficients are 0.20 for a waxy
floor, 0.50 for a shiny metal, and 0.80 for a clean mirror.  The
darker a surface material is, the more dominant the specular
reflection will appear, because of less competition from diffuse
reflection.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Mirror Coefficient
The Mirror Coefficient controls how clearly a material will
reflect the objects around it.  (Don't try to comb your hair
while looking in a concrete mirror, for a bad example.)  Good
examples are settings of 0.30 for a waxy floor, and 0.80 for a
chromed or mirrored surface.  

The higher the setting for Mirror, the sharper the reflection. 
Figure 5.11 shows materials with a mirror setting of 0.25 and
0.65,  and all other settings the same.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Transparency Coefficient
The Transparency slide bar/text box sets the percentage of light
transmitted through an object.  The higher the Transparency
coefficient, the more light is transmitted.  Completely opaque
materials have a Transparency coefficient of zero.  The
materials in BIG D's Reflective-transparent and Transparent
libraries have Transparency coefficients of 0.90.

The coefficient is measured as a percent of light transmitted
per unit thickness.  Thin objects transmit more light than thick
objects.  A material with a Transparency coefficient of 0.60
will transmit 0.60 of all light through a 1-unit thick object.  A
2-unit thick object will only transmit 0.30 of the light.  Clear
glass has a transmission coefficient of about 0.80.

Note:  If a transparent object has zero thickness (such as a 3D
face), BIG D will reduce the amount of light passing through
it as if it were one unit thick.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Smoothness Coefficient
The Smoothness coefficient controls how smooth a shiny
surface appears.  Very smooth specular surfaces exhibit small,
focused specular highlights.  Shiny surfaces that are rough
show specular highlights that are "grainy" and spread out.

The higher the Smoothness coefficient, the smoother a shiny
surface will appear, and the more concentrated its specular
highlights.  Chrome is typical of specular materials with high
Smoothness coefficients.

A low smoothness coefficient will result in a rough shiny
surface, such as jewelry with a "pebbly" surface, or brushed
metal fittings. The smoothness setting has no effect if the
specular reflection coefficient is zero.

In relation to bump maps, smoothness controls the "micro"
surface smoothness, while bump maps affect the "macro" 
smoothness.  A surface can be both bumpy and smooth.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Noise Coefficient 
Noise modifies the actual RGB values of a surface, giving it
a grainy appearance.  A higher setting for Noise gives a 
greater variation from the material color.  This is useful for
random textures such as grass, concrete, or sandstone. Noise
gives a greater realism to surfaces that would otherwise
be a single flat color.  Noise can be used in some large areas
that show a repetitive pattern if texture maps alone are used.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Refraction Index
The Refraction Index determines how much a light ray is
refracted, or bent, as it passes through a light-transmitting
material.

Settings run from 1.00 to 2.00, and are the same in BIG D as
in any table of refraction indices.  (Most books on optics
include refraction indices.)  The closer the Refraction Index to
1.00, the less the light rays are refracted.  (A value of 1.00
means no refraction at all.)  A refraction index of 2.00 will
exhibit maximum refraction.  Refraction results in the distor-
tion of objects which can be seen through the light-transmitting
object.

A refraction index of 1.33 is typical for water.  The refraction
index has no effect on materials with a zero Transparency
Coefficient.  

Objects must contain a closed volume in order to refract
transmitted light.  Examples of objects which contain closed
volumes include closed extrusions made up of LINES and
ARCS, surfaces of revolution created by BDRSURF whose
cross-sections are a closed shape, and extruded SOLIDS.

Objects which are planar in nature will not refract transmitted
light.  Planar objects include 3D FACES, 3D MESHES,
extrusions which do not form closed shapes, surfaces of
revolution created by BDRSURF whose cross-sections are not
closed shapes, and closed shapes with zero thickness.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Material Properties Options
At the bottom of the Material Properties dialog boxes is a
group box named Options.  It contains toggles for Internally
Reflective, Casts Shadows, Can Be Shadowed, and Metallic.

The Image File dialog box (Options menu) contains global
settings for reflections, shadows, and transparency that affect
the whole rendering.  These options override the settings for
particular materials in the Material Properties dialog box.
For example, if you want your rendering to show shadows, you
must leave [Shadows] toggled on in the Image File dialog box. 
Then toggle on [Casts shadows] and [Can be shadowed] for
each material that you want to exhibit these properties.

If you want to do a preliminary rendering of a scene to check
lights, view, and materials, you can turn off Options to speed
up rendering time.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Internally Reflective
In addition to surface reflections, an object may exhibit re-
flections within itself.  This option can be enabled only when
the material concerned has a non-zero setting for Transparency
and Mirror.  Internal reflections occur when light strikes the
inside surface of a transparent object at a shallow angle.  

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Casts Shadows
If you toggle off [Casts Shadows] for a particular material, the
object to which that material is assigned will not cast shadows,
but the surfaces of the object will be shaded according to their
orientation to the lights in a rendering.  The  default for
[Casts Shadows] is On.  

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Can Be Shadowed
If [Can Be Shadowed] is toggled Off for an object, shadows
from other objects will not appear on that object, although the
object's planes will be shaded according to their orientation to
the light.  Toggling [Can Be Shadowed] Off saves time
during preliminary renderings.

You can also toggle Off [Can Be Shadowed] for the final
rendering, to get rid of inconvenient shadows.  For example,
if you construct a curved "sky" backdrop behind your model,
and the lighting setup you need throws shadows onto the
"sky", you can eliminate the shadows by toggling off [Can Be
Shadowed] for the backdrop.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Metallic
The "Metallic" setting for an object means that it will reflect
light as a metal does.  The ON setting for metal objects means
the highlight on an object will be the color of the object, and
OFF means the highlight is the color of the light source.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Material Texture Dialog Box
BIG D can easily map real-world textures, such as woodgrain
or brick, to objects in your rendering.  A texture map is a two-
dimensional image of a pattern or object.  Any file with a
TGA, PCX, WIN, or GIF format can be used as a texture map
with BIG D. 

This is important: - a material and a texture
are not the same thing.  They might sometimes seem
identical, because BIG D's texture maps are assigned to
materials that have the same name.  For example, the texture
file "marbltan.gif" is assigned to a material named "marble-
tan".  Any texture file may be assigned to any material in BIG
D's libraries.  The texture map will override the material color
settings of the base material. 

The texture maps that come with BIG D are in the bigd.bdm
library. You can tell BIG D to repeat a texture pattern
infinitely, to cover any size object.  You can also set the
rotation angle, width, and height of the texture map.  

Text Box

There are two sensible things you can do with the Material
Texture dialog box.  (If you want to do something silly - for
example, assign the texture file "grass" to the material named 
"marble-tan" - see the chaplain.)  One reasonable procedure
is to edit the map attributes of a texture file assigned to the
current material.  The other reasonable procedure is to assign
an imported texture file to one of BIG D's materials.

The Material Texture dialog box comes up with the name of
the current material on the title bar.  If the current material
has a texture map, the name of the texture file is in the "Name:"
text box just below.  If you want to change the map attributes
for the texture file assigned to the current material, leave the
Name text box alone.

If you want to assign an imported texture file to one of BIG
D's materials, first select a base material using the Materials
dialog box, define it as a new material using the [Add New
Material] button, and type in a new name.  When you call up the
Material Texture dialog box, the new material name will be on the
title strip, and you can pick a texture file from the Files
scroll box to assign to it.

Directory

The "Directory:" line displays the full path and name of the
texture file which is currently assigned to the material.  If no
texture is assigned to the material, the Directory line displays
only the path to the current texture directory.

Type

Below the Directory label is a scroll list labeled "Type:" which
filters for texture map format.  All of BIG D's texture maps
are GIF files, and GIF is the default.  Unless you've imported
texture files in TGA, PCX, or WIN formats, changing Type to
anything but GIF simply empties the scroll box.

File and Directory Scroll Boxes

Use the Files and Directories scroll boxes to select a file from
anywhere in your system.  Scroll through Directories to locate
the appropriate entry, and do the same with Files.

Map Attributes

The Map Attributes group-box at the bottom of the Material
Texture dialog box contains a scroll list labeled "Repeat", text
boxes labeled "Width:" and "Height:", text boxes and slide bars
for Rotation and Antialias, and a toggle button, [Black pixels
invisible].

\Repeat
"Repeat" allows you to repeat a texture map infinitely in all
directions.  Texture maps usually need to cover surfaces which
are larger than the map itself.  Three Repeat mode options are
available: Off, Normal, and Reflect.

If the Repeat mode is Off, BIG D will not repeat the texture
map.  Use this option for textures which do not repeat: a
painting, tree, or human figure.  If the Repeat option is set to
Normal, the texture map is repeated in all directions
sufficiently to cover the object to which it is assigned.  This
option works well for regular textures, such as brick, in which
the left and right edges, and the top and bottom edges, of the
texture match.  

If the opposite edges of the texture map do not match, the
Normal repeat mode will show seams at the edges of the map. 
Use the Reflect setting of the Repeat mode to eliminate the
seams.  The Reflect setting repeats the texture sufficiently to
cover the object, but also reflects the texture as it is
repeated.  This option works well for irregular textures
such as wood grain or marble.  

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Map Width and Map Height
The map Width and Height text boxes control the scale of the
texture map.  It is important that you supply reasonable values
for the map width and height.  If a textured object appears to
be incorrectly textured, it is probably because the map Width
and Height are not set properly.

The Width of the map is the horizontal width of the file's
image in real world units.  The Height of the map is the
vertical size of the image in real world units.  The default unit
is inches, but you can change it to anything from feet to
kilometers using the Display dialog box on the Options menu.
The lower left corner of the texture map is considered the
origin.  The origin of the texture map will correspond to the
local origin of the entity to which the texture is mapped.
For example, if a texture is mapped to a circle whose center is
located at 0,0 in the circle's User Coordinate System, the lower
left corner of the texture will be mapped to the center of the
circle.  The texture map will repeat out from the origin, if
Repeat is set to "Normal" or "Reflect."

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Map Rotation Angle
The rotation text box/slide bar allows you to rotate the texture
map before it is mapped to an object.  The angle of rotation is
measured in degrees in a counter-clockwise direction from the
object's positive x-axis.  

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Antialias
Occasionally, a texture map that is far from the camera will
show an interference (or moire) pattern superimposed on the
texture.  Rectilinear texture maps, such as wood paneling or
concrete block, are more likely to exhibit this effect.

The range for Antialias is 0 to l.00.  If an interference pattern
shows up in your rendering, you can get rid of it by adjusting
Antialias upward from its default of .50.  The higher settings
disguise the interference pattern.  Don't set Antialias any
higher than necessary: the maximum setting of 1.00 completely
blurs out the texture, turning the red and white checkerboard
to solid pink, for example.

\Black Pixels Invisible
If you are using a single unit texture map, such as a tree or
human figure, you must toggle On [Black Pixels Invisible] on the
Material Texture dialog box to make the unmapped area of the
mounting board disappear.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Material Bump Dialog Box
A bump map creates an illusion of surface detail by faking
protrusions and indentations on a surface.  The surface features
appear to cast shadows, based on the direction of the light
sources you have defined.  The bump map assigned to a
surface in your model works by altering the surface reflection
calculations (surface normals) according to the intensities of
the image file used to generate the bump map.
3D Model Bump Maps

You must create your own bump maps to use with BIG D. 
The most common, and flexible, procedure is to make a three-
dimensional model with the surface contours you want.  As
example, if you want to render a standing seam metal roof, you
can use your modeling program to draw a profile of the roofing
contour, extrude it into a corrugated plane, and use the model to
generate a metal roof bump map.

When you toggle on [Generate Bump Map], BIG D calcu-
lates a greyscale image file from the model, assigning the
highest elevations of the bump map to the portions of the
model closest to the camera, and the lowest elevations to the
portions farthest away.

Once you have made the greyscale image file, you can apply
the bump map to either a solid color, or to a texture map.

If you apply the bump map to a color, all of the color's
material properties affect the bump map.  For example, if you
apply a map with hemispherical depressions to a shiny green
color, and then assign the color/bump map to a sphere, you get
a shiny green golf ball. 

If you apply this type of bump map to a texture map, the
texture map will also retain its pattern, colors, and material
properties.  The applications for this procedure are limited to
special cases where the pattern of the texture, and the pattern
of the bump map's altered surface normals combine in some
reasonable manner.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Bumping a Texture Map
The other way to create a bump map is to generate one di-
rectly from a texture map.  If you generate a bump map from
a full-color image file, BIG D will sum the RGB components
to determine total intensity-as if you had taken a black and
white snapshot of a color picture.  The lightest portion of the
image will be the highest elevation of the bump map, and the
darkest portion will be the lowest elevation.  

This is simpler than making a 3D model, but in a few cases,
this process can produce an inaccurate reflection of the true
contours of the material you are rendering.  For example, if
you bump a texture map of red brick with white mortar, the
lighter mortar will appear to ooze out from between the darker
bricks, rather than to be struck back behind the plane of the
bricks.  You can set Maximum Elevation to a negative value
in order to correct this effect.  This will make the lighter
elements appear to recede instead of protrude.

To bump a texture map, first choose a texture map as the
Current material on the Materials dialog box, then
pick the Add New Material button.  Then go to the Material
Bump dialog box.  Pick the same texture from the Files scroll
box, which assigns it to the Current material.  Set Map At-
tributes - Repeat Mode, Width, Height, Rotation, and Antia-
lias - as you would for a texture map.  Then set the Maxi-
mum Elevation for the bump map.  Use Show Material to test
the new bump map.

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Maximum Elevation
The "Max. Elev:" text box is the only feature on the Material
Bump dialog box that is different from the Material Texture
dialog box.  Use it to type in a value for the maximum dis-
tance between the highest and lowest points in the bump map.

The apparent height and depth of a bump map's surface details
are controlled by the "Max Elev:" setting.  The edge of a
bump-mapped object will not show the protrusions and
indentations in profile, because they aren't really there.  If
you set maximum elevation too high, the illusion of depth is
destroyed by this edge effect.  

<SEE ALSO>
Add or Delete a Material
Black Pixels Invisible
Casts Shadows
Copy Library
Copy Material
Delete Material
Diffuse Reflection Coefficient
Edit Texture procedure
Internally Reflective
Map Rotation Angle
Map Width and Map Height
Material Bump Dialog Box
Material Operations
Material Properties Dialog Box
Material Properties Options
Material Texture Dialog Box
Materials Dialog Box
Materials Procedure
Materials Scroll Box
Maximum Elevation
Metallic
Mirror Coefficient
Noise Coefficient
Reflections
Refraction Index
Repeat
Single Unit Texture Procedure
Smoothness Coefficient
Textures
Transparency
Transparency Coefficient
Ambient Reflection Coefficient
Specular Reflection
Bumping a Texture Map
Can Be Shadowed

\Display Dialog Procedures
1.  Pick [Options] from the main menu, and [Display] from
the pull-down menu.

2.  Use the [Angular units] scroll list to specify Degrees,
Gradians, or Radians.  Degrees is the default.

3.  Set [Linear units] to the units used in your three-dimen-
sional model - inches, feet, miles, millimeters, centimeters,
meters, or kilometers.  Inches is the default.

4.  Specify an RGB or HSV [Colorspace].  HSV is the
default.

5.  Set [Angular snap] to a "round off" value for the units you
specified in [Angular units].  

6.  Set [Linear snap] to a round off value as well.  For
example, if you want linear distances rounded to the nearest
quarter inch, set [Linear units] to inches and [Linear snap]
to .25.
\Image File Procedures
1.  Pick [Options] from the main menu, and [Image File]
from the pull-down menu.

2.  Use the [Resolution] scroll list to specify an image size
compatible with your rendering device.  All of your favorite
sizes, from 320 x 200 to 1280 x 1024, are listed.

3.  Use the [Format] scroll list to specify GIF, PCX, WIN, or
TGA image (rendering) files.  GIF is the default.

4.  Leave [Bits per pixel] set at the default of 8 unless you
have a card/monitor capable of displaying more than 256
colors.  Only the TGA (TARGA) and WIN formats allow 16,
24, or 32 bit settings.   Eight bit images display 256 colors, 16
bit images display a maximum of 32,768 colors.

5.  Leave [Pixel aspect ratio] at the default unless you want
to  distort the image.  BIG D automatically adjusts the ratio
when you change screen Resolution.

6.  Toggle on [Run-length encoding] if you know how you
will use the finished rendering.  Run-length encoding com-
presses the image file, which conserves disk space, but
compressed images are not as portable as uncompressed image
files.

7.  Leave [Samples per pixel] set to 1 for most situations. 
Switch to higher settings if you want to reduce the jaggies
(stair-stepping of diagonal lines and edges).  Higher settings
increase processing time dramatically.

8.  Set [Grid size] to 4 for draft renderings, and lower for
finished renderings.  If the rendering is missing small details,
you need to set [Grid size] lower to catch the small details.

9.  Set [Dithering] to 1 for preliminary renderings.  Higher
settings give all the objects in a scene a grainier appearance.
A setting of 0 produces "color banding," or unblended color
bands in your image, but shiny objects appear shinier.

10.  Toggle on [Fast shade] to do a rough rendering; it speeds
up the rendering calculations.  Fast shaded images are used in
the draft stage of the rendering process.

11.  Toggle off [Reflections], [Shadows], and [Transparen-
cy], if you want to save processing time on a preliminary
rendering.

<SEE ALSO>
Options Menu
Angular Snap
Angular Units
Colorspace
Display Dialog Box
Display Dialog Procedures
Linear Snap
Linear Units

\Expert Dialog Procedures
1.  Pick [Options] from the main menu, and [Expert] from the
pull-down menu.

2.  The [Ray depth] default is 4.  This setting determines the
maximum number of reflections for each light ray.  Higher
settings can be used to add realism to scenes which contain
glass and other transparent objects.  Higher settings can also
increase processing time dramatically, but usually don't, as it
is rare for a ray to reflect more than four times.  The excep-
tion: scenes that contain a lot of chrome and mirror surfaces.

3.  The default for [Light], [Space], and [View bucket size]
is 200.  Leave the settings at the default unless you have
trouble rendering.

4.  Toggle on [Erase rendering file] before you start render-
ing, if you're running out of room on the hard drive.  BIG D
will erase the rendering file after generating the final image
file.  (Remember that the rendering file may speed things up,
if you re-render the same file with different settings.)

5.  Toggle on [Generate bump map] if you want to generate
a gray scale image from a texture map - the gray scale image
encodes value differences that determine the respective
elevations for a bump map.

Bucket Size
Erase Rendering File
Expert Dialog Box
Expert Dialog Procedures
File Compression
Generate Bump Map
Ray Depth

\Display Dialog Box
Use the Display dialog box to customize your interface by
specifying linear and angular units, colorspace, and linear and
angular snap.  It is conceivable that you will set Display
parameters once, and never reset them.

<SEE ALSO>
Options Menu
Angular Snap
Angular Units
Colorspace
Display Dialog Box
Display Dialog Procedures
Linear Snap
Linear Units

\Angular Units
Angular units can be set to degrees, gradians, or radians. 
Degrees is the default.  Many of BIG D's Views and Lights
operations require angular unit measurement.  

<SEE ALSO>
Options Menu
Angular Snap
Angular Units
Colorspace
Display Dialog Box
Display Dialog Procedures
Linear Snap
Linear Units

\Linear Units
The default for linear units is inches.  BIG D accepts linear
units for inches, feet, and miles (if you think big).  You can
also specify metric system units with millimeters, centimeters,
meters, and kilometers.  You should specify the unit closest to
the units used to construct your three-dimensional model.

<SEE ALSO>
Options Menu
Angular Snap
Angular Units
Colorspace
Display Dialog Box
Display Dialog Procedures
Linear Snap
Linear Units

\Colorspace
You can specify either an HSV or RGB colorspace.  HSV is
the default, since it is easier to use intuitively for anyone
accustomed to using pigment colors.  

<SEE ALSO>
Options Menu
Angular Snap
Angular Units
Colorspace
Display Dialog Box
Display Dialog Procedures
Linear Snap
Linear Units

\Angular Snap 
Angular snap sets the round off value for angular units. 
Angles typed in, and angles reported by the interface, will be
rounded to the Angular snap value.  For example, if you want
angular measurements rounded to the nearest degree, set
[Angular units] to degrees and [Angular snap] to 1.

<SEE ALSO>
Options Menu
Angular Snap
Angular Units
Colorspace
Display Dialog Box
Display Dialog Procedures
Linear Snap
Linear Units

\Linear Snap 
Linear snap sets the round off value for the units specified in
the [Linear units] scroll box.  This setting uses a decimal
system.  For example, if you set [Linear units] to feet, and set
[Linear snap] to .01, BIG D will convert the dimension 5'- 8"
to 5.67'.

<SEE ALSO>
Options Menu
Angular Snap
Angular Units
Colorspace
Display Dialog Box
Display Dialog Procedures
Linear Snap
Linear Units 

\Image File Dialog Box
The Image File Dialog box contains settings for image size and
quality, and global toggle buttons for shadow casting and
transparency calculations.  You will use Image File frequently
to change settings for "rough draft" or  presentation renderings.

The Image File dialog box contains group boxes for File
Options, Image Quality, and Rendering Options.  Use the
settings on this dialog box to adapt BIG D to your system, and
to adjust quality for either a quick rough rendering, or a super-
slick presentation rendering.
<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Resolution
Use the Resolution scroll list to specify the size of the output
image.  Width and height are measured in pixels.  Typical
resolutions up to 1280 X 1024 are in the scroll list, or you can
pick "Custom," which allows you to enter any resolution up to
4096 x 4096. 

You were asked to set Resolution when you first installed the
program, and you probably set it to the maximum size
supported by your rendering device.  The setting on the Image
File dialog box overrides the installation setting, so that you
can change sizes for rough and presentation renderings.

If you're doing rough renderings, setting Resolution to 320 x
200 quickly generates a small "postage stamp" image that you
can use to check for major errors.

If you set a resolution size greater than the resolution set for
your rendering device (see "Setup"), BIG D will display the image
at 1/2, 1/4, etc. size, so that the entire image is displayed. 

You can render at very high resolutions in order to send the
image file to a slide-making service, or to view it on a higher
resolution system.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Format
Use the Format scroll list to specify the type of output file you
want.  BIG D offers four choices: GIF, PCX, WIN and TGA. 
The type selected depends on what further manipulations you
want to perform on your image file.  For example, if you plan
to view and modify the rendering using a paint program, then
you should specify one of the image file types supported by
the paint program.

The default file format is GIF.  GIF files are fairly compact,
and very portable.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Bits Per Pixel
[Bits per pixel] tells BIG D how many bits are needed to
specify each pixel color.  An "8 bit image" means that the
image can consist of a maximum of 2 to the 8th, or 256, 
colors.  Rendering devices which are limited to 256 colors
include the IBM VGA.

The correct setting depends on the rendering device you are
using.  If you are using a TARGA 16 or Vision 16, set this
option to 16.  TARGA 24, TARGA 32, Vision 32, and Vista
users should set [Bits per pixel] to either 24 or 32.

NOTE:  If you don't set [Bits per pixel] correctly, colors are
distorted on your rendering device.

Tip:  you can, with this option, create 24-bit images (using an
8-bit device) for hard copy printing.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Pixel Aspect Ratio
Pixel aspect ratio is pixel width over pixel height (for a single
pixel).  Pixel aspect ratio is used to adjust screen resolution
settings to a standard 4:3 screen size.  BIG D automatically
sets the correct Pixel aspect ratio for the [Resolution] setting
you have specified. 

If you have an unusual screen size or if you want objects in
the rendering to appear distorted (the Fun House Mirror
option), you can type in a factor to adjust the relative image
width and height.  To calculate the factor, divide your screen
width by height, then divide 1.333 by the result.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\File Compression
This file compression option tells BIG D whether to compress
the output image file as it writes it to disk.  BIG D uses run-
length encoding to compress the image.  Resulting files are
typically 25 to 75 percent smaller than uncompressed files.

GIF and PCX files are already compressed, and so are not
compressed further by this option.  Also, if you are using BIG
D-generated files with other software, leave [Run-length
encoding] off.  TGA/WIN files can be compressed, but some
software packages do not recognize compressed TARGA
format files. 

Bucket Size
Erase Rendering File
Expert Dialog Box
Expert Dialog Procedures
File Compression
Generate Bump Map
Ray Depth

\Samples Per Pixel
[Samples per pixel], or antialiasing, is a feature designed to
smooth out, or nullify, the "aliasing" characteristic of raster
graphics devices.  In order to draw a diagonal line or edge, a
raster graphics device must stairstep to conform to the pixel
grid, resulting in "aliasing," or the "jaggies."

Samples per pixel compensates for these jagged edges by
averaging each pixel with adjacent pixels.  The antialiasing
levels specify how many rays are sampled for each pixel.
1 =  1 ray per pixel
4 =  4 rays per pixel
16 = 16 rays per pixel

Leave [Samples per pixel] set to 1 for 256 color images.
Settings greater than 1 increase rendering time dramatically.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Grid Size
[Grid size] influences the level of precision with which BIG
D analyzes the 3D model.  The three settings are 1, 2, and 4
pixels per grid.  Fewer pixels per grid increases accuracy, but
requires more generation time.

When generating an image, BIG D does not determine the
intensity of every pixel in the image.  Instead, it divides the
screen into a grid and calculates the intensity of the pixels at
each grid intersection.  Grid Size determines the number of
pixels included in each grid.

Once the grid size is known, BIG D analyzes each square
individually.  If the corners of a square have the same intensi-
ty, all pixels in that square are set to an identical intensity.
If the intensities at the corners are different, BIG D divides
the square into four smaller squares.  The intensity at the
corners of each smaller square is treated in the same manner as
the initial square.

The process repeats until every pixel in the initial square is
either filled in or calculated.  This method saves significant
processing time, especially for large areas of constant
intensity.

Theoretically, the larger the grid size, the faster the image is
generated.  The only drawback to setting a large grid size is
that very small objects, thin horizontal or vertical elements, or
objects with sharp corners may be missed by the grid.  If you
find such areas incorrectly rendered, you should reduce the
grid size.

Set [Grid Size] to 4 for draft renderings, then set it to 1 for
the final rendering.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Dithering
When a surface is rendered with BIG D, its intensity changes
from one location to another, due to lighting, fade percentage,
and view location.  Since rendering devices are limited to a
finite number of colors, or intensity levels, sometimes there are
not enough colors available to obtain a smooth gradation of
intensity change across a surface.

This limitation of the rendering device results in a banding
effect where the surface changes from one intensity level to
another. [Dithering] helps eliminate this banding effect by
varying the intensity of each pixel by a random amount.  This
random dithering smooths gradual changes in the intensity level.

Use dithering for 8 and 16 bit images; the most practical
settings for [Dithering] these images are 1 or 2.  A zero
setting produces no dithering, which results in banding. 
Settings higher than 2 produce a progressively grainier effect. 
Set [Dithering] to zero for 24 bit images, since they have
enough colors available without dithering.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Fast shade
When [Fast shade] is toggled on, BIG D takes fewer samples
of the scene, thus reducing resolution.  This option also takes
shortcuts which may incorrectly render some pixels as back-
ground color.  It is useful for quickly generating preliminary
renderings. 

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Rendering Options
The Rendering Options group box toggles - Reflections,
Shadows, and Transparency - set global conditions for your
rendering.  If one of the Options is set to OFF, the Option is
disabled for every object in your rendering.  If one of the
Options is set to ON, then you can enable or disable the option
for each particular object by using the [Internally reflective],
[Casts shadows], and [Can be shadowed] toggles on the
Material Properties dialog box.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Reflections   
If you assign reflective materials to the objects in your model,
BIG D calculates the reflected images of other objects on their
surfaces.  This capability can dramatically increase the realism
of a scene.  

Reflections can add substantially to the time required to
generate an image, especially if you have many reflective
surfaces.  The [Reflections] option lets you turn off reflection
calculations to speed image generation.  If you toggle [Reflec-
tions] Off, reflective objects still appear shiny in the
rendering, but they do not reflect other objects.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Shadows
BIG D calculates shadows cast onto objects by other objects. 
Like Reflections, this feature adds greatly to the realism and
depth perception of the rendered image.  Shadow calculations
also add to the image generation time.
You can toggle [Shadows] Off to save generation time on
rough renderings.  Shaded surfaces (surfaces facing away from
a light) are still rendered correctly, but shadows are not cast.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel
\Transparency
If you assign transparent materials to objects in your model,
BIG D will calculate the refraction effects of the light rays as
they are transmitted through the material.  This process is
called transparency mapping.

Transparency mapping can add significantly to the realism of
your rendering, but also to image generation time.  The default
setting for [Transparency] is ON.  Toggling [Transparency]
off will cause all objects which are assigned light-transmissive
materials to appear opaque.  Leave [Transparency] set to off
for quick draft renderings, and for renderings that do not
include transparent objects.

<SEE ALSO>
Dithering
Fading and Fog
Fast shade
Grid Size
Image File Dialog Box
Image File Procedures
Pixel Aspect Ratio
Resolution
Samples Per Pixel
Shadows
Antialias
Bits Per Pixel

\Expert Dialog Box
The Expert dialog box specifies ray depth and bucket sizes -
again, settings that don't need adjustment for every new
rendering.  Ray depth and "bucket size" control the ray tracing
calculations.  Use the [Erase rendering file] toggle to
conserve disk space, and the [Generate bump map] toggle to
create gray scale image files used in bump mapping.

The Expert dialog box contains text boxes for Ray Depth and
Light, Space, and View Bucket Size, all of which affect the
complexity of the ray tracing. Toggles for Erase Rendering File  
and Generate Bump map are also provided on this menu.

Bucket Size
Erase Rendering File
Expert Dialog Box
Expert Dialog Procedures
File Compression
Generate Bump Map
Ray Depth

\Ray Depth
To grossly simplify, a ray tracing program follows a ray of
light from the viewpoint through a pixel on the screen until it
hits an object in the scene.  Then the ray may be absorbed by
the object, transmitted through a transparent object, bounced
out of the scene, or bounced off the object to hit another
object.

[Ray depth] specifies the maximum number of ray bounces
that BIG D will calculate.  The default is 4, and ray tree depth
rarely exceeds this number, so higher settings usually have
little effect on speed.  [Ray depth] can be set as high as 10,
however.  The effect of ray depth is most critical when
rendering reflective surfaces, from which light bounces more
than 4 times.

Bucket Size
Erase Rendering File
Expert Dialog Box
Expert Dialog Procedures
File Compression
Generate Bump Map
Ray Depth

\Bucket Size
A ray tracing program tests each ray to see if it intersects any
of the objects in a scene.  If each ray were tested for each
object, the process would take a very long time.

"Bucket Size" is a search system that works by dividing the
volume of a scene into sampling modules.  This system saves
time by eliminating - in large chunks - areas that are not
affected by a particular ray.

If the ray intersects nothing in a "bucket," the scan moves on
to the next bucket.  If the ray does intercept an object in the
bucket, then the scan is over, no more buckets need be
searched.

The [Bucket size] setting specifies the maximum number of
objects per bucket.  Higher settings require less RAM.  The
division of the scene into sub-volumes is not affected by the
blocks and layers of the model.  

The default setting for Bucket Size is 200.  Don't change
it unless you get an out-of-memory error message.  

Bucket Size
Erase Rendering File
Expert Dialog Box
Expert Dialog Procedures
File Compression
Generate Bump Map
Ray Depth

\Erase Rendering File
During the rendering process, BIG D creates both an image
file and a rendering file.  The image file is a pixel map or bit
map; the rendering file stores calculations which will speed
future renderings of the same scene.  

Rendering files can eat up disk storage, but also can save time
in successive renderings of the same scene.  Thus the render-
ing file is not essential, but very helpful if you need to do
further renderings of a scene.

If you toggle on [Erase rendering file] and proceed with
specifying all the necessary variables (lights, views, materials,
etc.), BIG D will generate both rendering and image files, and 
erase the rendering file once the image file is produced.  The
default setting for [Erase rendering file] is "Off".

Bucket Size
Erase Rendering File
Expert Dialog Box
Expert Dialog Procedures
File Compression
Generate Bump Map
Ray Depth

\Generate Bump Map
[Generate bump map] creates a greyscale image file when
you render the scene.  The image file can then be used to set
height variations on bump-mapped surfaces.  The program sets
pixel intensity based on the distance of an object from the
camera, with higher = closer and lower = farther away. 

The default setting for [Generate bump map] is OFF.
[Generate bump map] should be set to ON only if you are
creating a greyscale image.

Bucket Size
Erase Rendering File
Expert Dialog Box
Expert Dialog Procedures
File Compression
Generate Bump Map
Ray Depth

\Lights Menu Overview
BIG D offers several types of lighting for illuminating your
model.  The Lights menu allows the use of Point, Spot, and
Directional lights, the Sun, Ambient and Background light, and
X-ray lights.  It also allows you to control the fading of light
with distance, and fog.

All lighting options are accessed through the Lights menu. 
The Lights menu lists four dialog boxes: Add Light, Delete Light,
Edit Light, and Lighting Options. 

(Lighting Options controls Ambient Light, Background, and
Fading/Fog operations.)  If no lights are defined in the scene,
the Delete Light and Edit Light options are disabled. The
lighting equipment supplied by BIG D falls into two
categories - global and local.  The global operations accessed
from Lighting Options (Ambient Light, Background, and
Fading/Fog) affect the whole rendering in a consistent manner. 

The options accessed from the Add Light dialog box - Point,
Spot, and Directional lights, as well as the Sun - locate
specific lights in a specific place, and cast shadows in 
specific directions.  The X-ray light option can be activated for
any of these lights. 

BIG D allows you to define any number of directional, point,
and spot lights, and the program compiles a list of the lights as
you define them.  You must always define at least one light to
generate an image. If you are not familiar with the program, it
is best to start with neutral-color lights at default brightness
settings.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Lighting Options Procedures
1.  Pick [Lights] on the main menu bar, and [Lighting
Options], which controls Ambient Light, Background, and
Fading/Fog, from the pull-down menu.

2.  In the Ambient Light group box, use the Hue, Saturation,
and Value slide bars (or RGB slide bars) to define the color of
the light (or pick the text box, type in a number, and press
[Enter]).  The color patch will change as you change the color
settings. Use the Brightness text box to specify Ambient Light
brightness. 

3.  Select a color for Background using the HSV slide bars or
text boxes in the Background group box.

4.  Establish Fading parameters by specifying a percentage in
the Maximum fade text box/slide bar. Leave the start and end
distances at default settings except for special cases.  Toggle
on Fog if you want to use it. 

5.  When you are satisfied with your choices, pick the [OK]
button, which returns you to the main menu bar.  Picking
[Cancel] will abort any changes that you made.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Define a Light Procedure
1.  Pick [Lights] from the main menu, and [Add Light] from
the pull-down menu to call up the Add Light dialog box.  BIG
D will assign consecutive numbers to lights as you define
them.  (The title of the Add Light dialog box will be "Light
#1" for the first light, and so on.)

2.  BIG D assigns a default name to each light. The default
name is the first four letters of the BDS file name and a four-
digit number (e.g. "LOGO0001"). If you don't want to use the
default name, pick the text box labeled "Name:" and type in a
new name. Then press [Enter].

3.  Toggle the X-ray light button On or Off.  (X-ray lights are
used to bring out detail in shadows.)

4.  Specify color for the light using the text boxes/slide bars
labeled Hue, Saturation, and Value in the Color group box. 
The color patch will change as you change the settings.  Set
Brightness by picking the text box, typing in a number, and
pressing [Enter].

5.  Using the scroll list button labeled "Type," select a type of
light: Point, Spot, Directional, or Sun.  

6.  Each different type of light has its own Geometry dialog
box.  Pick the Geometry button to call up the appropriate
dialog box.

7.  Use the Geometry dialog box to locate the light in relation
to your model. When you have located the light, pick [OK] to
return to the Add Light dialog box.

8.  When you have defined the light to your satisfaction, pick
[OK].  Pick [Cancel] if you wish to get rid of your changes.

When you pick [OK] or [Cancel], the Edit Light dialog box
appears in case you want to do any last minute editing.  Pick
[Done] to return to the main menu bar.

9.  If you wish to define another light without returning to the
main menu bar, pick [Add New Light], which calls up a fresh
Add Light dialog box for the next light.  If you have defined
a series of lights and wish to go back to the previous light,
pick [Previous Light].

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Delete a Light Procedure
1.  Pick [Lights] from the main menu bar, and [Delete Light]
from the pull-down menu.

2.  If you have defined only one light, a screen appears that
asks, "Do you really want to delete Light #1?"  If you really,
really want to, pick [Yes]; if you want to think about it some
more, pick [No] to return to the main menu bar.

3.  If you have defined more than one light, picking [Delete
Light] calls up the Delete Light dialog box, which contains a
scroll box labeled "Light," and lists all of the lights which
have been defined.  

4.  Pick the light that you wish to get rid of (the light name
will highlight in the scroll box) and then pick the [Delete
Light] button.  A screen will appear asking if you really want
to delete the light.  Pick [Yes].  (Picking the [Done] button on
the Delete Light dialog box will send you back to the main
menu without deleting anything.)

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Edit a Light Procedure
1.  Pick [Lights] from the main menu bar, and [Edit Light]
from the pull-down menu.

2.  If you have defined only one light, picking Edit Light will
send you to the dialog box for that light, which is identical to
the Add Light dialog box.

3.  Make the changes you need, using the same operations that
you used to define the light originally.  When you have
finished, pick [OK].  The Edit Light dialog box (see below)
will appear.  Pick [Done] to return to the main menu bar.

4.  If you have defined more than one light, picking Edit Light
from the pull-down menu will call up the Edit Light dialog
box, which contains a scroll list of the lights defined.  Pick
the light you wish to edit, and then the [Edit Light] button, to
call up the light's dialog box, which is identical to the Add
Light dialog box.

NOTE: If you wish to edit any of the Lighting Options, simply
pick [Lighting Options] from the pull-down menu to get the
same dialog box that you used.  Change Ambient Light,
Background, or Fading settings and then pick [OK].

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Ambient Light
Ambient light is background light which is applied to all
surfaces equally, regardless of their location or orientation. 
Ambient light is used to simulate light which is reflected from
the atmosphere, and from other objects in the scene.

Without Ambient light, surfaces which are shaded from all
other light sources will appear black, similar to photographs
taken on the surface of the moon.  Use Ambient light to
illuminate surfaces which are in shade.

Ambient light has no location or direction and is not part of
the light list.  Ambient light will only illuminate materials
which have a non-zero Ambient Reflectivity Coefficient.
Adjust Hue, Saturation, and Value (or Red, Green, and Blue)
using the slide bars or text boxes.  If you are using the HSV
colorspace, Hue is a number between 0 and 360.  Saturation is
a percentage, with 0 being completely unsaturated (no color),
and 1 being the fully saturated hue.  Value ranges from 0
(black) to 1 (white).  Check your results with the color patch. 
For normal use, Ambient light color should be kept close to
neutral by setting Saturation close to 0, and Value close to 1. 

Ambient Light's brightness is measured as an absolute number
from 0 to 100 (not a percentage).  Typical brightness values
for Ambient Light vary from 1 to 3.  The default value is 1. 
When you have defined the full array of lights in a rendering,
you may need to adjust Ambient light.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Background 
The Background of your rendering functions as both light and
color.  The color setting for Background determines the color
and brightness of any image pixel which does not intersect an
object in the scene.

For example, suppose you want to render a cam shaft.  If you
show the cam shaft "floating in space," every part of the screen
that is not the object "cam shaft" is Background.  

However, if you construct a table to put the cam shaft on, and
a flat plane to serve as a backdrop behind the table, the table
and backdrop are defined by BIG D as objects, and are not
affected by the Background definition.

The Background area will not reflect light back into the
rendering.  However, if the rendering contains shiny surfaces,
those surfaces can reflect the background color.

In the Background group box, set color for the Background
pixels using the Hue, Saturation, and Value (or RGB) slide
bars or text boxes.  As in Ambient Light, Hue is a number
between 0 and 360, and Saturation and Value are percentages.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Fading and Fog
The Fading option controls the amount that light diminishes as
it travels through space; objects far away from the screen are
darker than objects close to it.

The default setting for Start distance is zero, which is at the
camera.  End distance defaults to twice the distance from the
camera to the farthest point of the model.  For most render-
ings, you should leave these settings as is.  (If, for some
reason, you want to set up a more extreme light fall off,
decrease the End distance setting.)

Maximum Fade is a percentage - the value difference
between the start and end point.  The default for Maximum
Fade is 0.50.  If you want less fading, set Maximum Fade to
a smaller value.  Increase the Maximum Fade percentage to darken
the scene more drastically.

Fog diminishes the sharpness of objects as they recede from
the camera - sort of like, well, fog.  It mimics the effect of
the atmospheric perspective often seen in paintings and
photographs.  Fog operates by mixing in pixels of Background
color with the pixels of the model's material color.  Toggle on
Fog to add a diffusing effect to the darkening obtained by
using Fading.

The "thickness" of Fog is determined by the Maximum Fade
percentage.  Thickness is a linear gradient or buildup from
near distance, where it starts at zero thickness, to far
distance, where the full percentage you specify takes hold,
staying in place out to infinity.  Even if 1.0, or 100% fog, is
specified, there will be no fog in the near distance; the 100%
will take effect at the far distance, and stay in effect to
infinity.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Add Light Dialog Box 
Selecting Add Light from the Lights menu calls up the Light
dialog box, used to add or edit individual lights.  BIG D will
automatically number the lights that you define.  The first time
you select Add Light, the dialog box will appear with the title
"Light #1". 

Name

In the upper left corner of the dialog box is a text box labeled
"Name:".  BIG D assigns a default name to each light as you
define it - the first four letters of the BDS file, followed by
a four-digit number, beginning with 0001.  If this seems
unnecessarily boring, or if you wish to categorize your lights
in some way (e.g. neon0001, neon0002), you can assign names
to the lights by picking the text box, typing in the new name,
and pressing [Enter].

Type of Light

Use the "Type" scroll list to designate a light as Directional,
Point, Spot, or the Sun.  Pick the box and hold down the pick
button to call up the list of types.  Move the cursor over the
type you want and release the button.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\X-Ray Lights
Use the X-ray toggle button at the top right of the dialog box
to specify whether or not any defined light - Point, Spot,
Directional or Sun - is an X-ray light.  An X-ray light is a
special type of BIG D light that does not cast shadows.

The term "X-ray" does not refer to seeing the insides of things,
as does a medical X-ray; BIG D's X-ray lights shine through
things, like Superman's X-ray vision.  

X-ray lights brighten surfaces in a scene according to the angle
of the surface in relation to the direction of the light.  The
more nearly perpendicular a surface is to the light's direction,
the more X-ray light it receives.  

X-ray lights are useful for lightening cast shadows and
modeling shaded surfaces. Cast shadows can either aid or damage
the illusion of three-dimensional reality.  A set of cast shadows
from a dominant light source gives the eye clear and simple depth
cues, whereas multiple sets of shadows from multiple light
sources can become confusing and cluttered. 

Shadows cast by a single light source in a rendering are
usually too black to look realistic, unless Ambient light is
adjusted to compensate.  If increasing Ambient light enough to
brighten shadows washes out the rest of the rendering, you can
use X-ray light to brighten selected surfaces only.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Color
A material's hue is the "color" of the material.  Hue is defined
as an angle between 0ø and 360ø on a color wheel.  Red is at
0ø, green at 120ø, and blue at 240ø.  Select a material's hue
with the Hue slide bar, or type a number, and press [Enter].

Use the Material Properties dialog box to create new colors by
editing existing colors.  The Color group box contains three
slide bars and text boxes, and a color patch.  The color patch
changes continuously to show the effect of your adjustments.
You can specify either an HSV-based color model or an RGB
color model when you use the Display dialog box in the
Options menu.  The HSV model is the default.

The combination of settings you specify on the Hue, Satura-
tion, and Value (or RGB) slide bars defines the color of the
light. Keep the color close to neutral unless you're
setting up a special effect, such as stage lighting.

The Brightness text box sets the intensity of the light on a
scale of whole numbers from 1 to 100.  The default value is 1;
typical values are 1 - 4.  As more lights are added to a scene,
the brightness increases cumulatively.  The more lights used,
the lower the brightness should be for each individual light. 
You'll probably have to go back and adjust brightness after
you have specified all the necessary lights.

<SEE ALSO>
RGB Model
HSV Model


\Light Geometry
After you select a type of light, pick the Geometry button to
call up the appropriate dialog box for locating that type of
light.  Keep a light located outside of the visible area of the
rendering, unless you model a light fixture to contain it, or
unless you intend to use it as a UFO.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Point Lights
A point light is located at an infinitely small point in three-
dimensional space, defined by its x, y, and z coordinates.  A
point light radiates light rays in all directions equally.  
Light bulbs are examples of point lights.

A "Fading" group box appears at the bottom of the Geometry
box for this light.  The fading effect begins at the camera lens
(or at zero), where the point light is at 100% intensity, and
increases in a linear manner, until it reaches the point
determined by the fade distance value.

"Fade" is the amount of fading, as a value between 0.0 and 1.0 -
the default is 0.5.  When the fade distance is reached, the
fading stays at the level determined by "Fade" (0.5, say), from
the fade distance out to infinity. 

There are two ways to locate a point light:

1.  Use the Source text boxes in the Point Light Geometry
dialog box to enter x, y, and z coordinates.  You do not have
to specify a target for a point light since it shines equally in
all directions.  When you enter new values in the text boxes, the
light icon in the viewports will change position to match the
new coordinates.

2.  Use the Top and Front viewports to graphically locate a
point light in relation to the wireframe model.  The Top
viewport shows the light icon's location relative to the x-y, or
"ground" plane.  The Front viewport shows the altitude of the
light on the z-axis (the height of the light).  Point light icons
are eight-rayed circles. 

Move the cursor over the light icon in the Top viewport.  Click
to select the light, and hold down the button.  Use the mouse
to drag a rubberband line from the light icon to a new position. 
When you release the pick button, the icon snaps to it.

Then move the cursor to the Front viewport and repeat the
operation to raise or lower the light.  As you drag the light
around in the viewports, the numbers in the  x, y, and z text
boxes will change to reflect the new positions.

Note:  If you can't see the icon in the viewports, it is probably
located too far from the model to be within the border of the
viewport.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Spot Lights
A spot light is similar to a point light that has been fitted
with a reflector, which corrals the light rays into a cone.  The
angle, or spread, of the light cone is adjustable.  Spot lights
can be aimed at any area of a scene.

The Spot Light Geometry box requires you to position both the
light's Source and its Target, and to specify a Spread Angle
for the light.  Changing the "Fading" default settings is
optional.

There are two ways to locate a spot light:

1.  Use the Source and Target group boxes.  Enter x, y, and z
coordinates in the Source text box. Do the same operation to
locate the Target. 

2.  Use the viewports to graphically locate the Light and its
Target with the mouse.  The Target icon is a box with an X
inside, and the Light icon is an eight-rayed circle.  As you
move the icons, the text box values will change. 

You must also specify the spread angle of a spot light using
the Hot spot (default 50) and Fall off (default 60) text boxes
in the Spread Angle group box.  "Hot spot" is the full-intensity
area or cone of the spot light.  "Fall off" is the cone of
lessening intensity from the Hot spot cone to the surrounding
darkness (or otherwise-illuminated area).

In selecting a spread angle, consider whether to illuminate the
entire scene, or highlight a particular area.  The area lit
depends on the distance from the target to the light.

A "Fading" group box appears at the bottom of the Geometry
box.  "Fade" is the amount of fading, as a value between 0.0 and
1.0, and the default is 0.5.  The process is this: the fade
effect is zero at the (spot) light's source, and increases on a
linear gradient out to the fade distance specified, where its
effect becomes constant (the constant 0.5, or whatever you've
entered in "Fade") from there to infinity.  

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Directional Lights
A directional light emits rays which are parallel to each other,
as if the light were located an infinite distance from the scene.
Because a directional light is located along a vector, rather
than at a specific distance from the model, there is no icon in
the viewports to show its location; the only way you can locate
a directional light is by using the Geometry dialog box.    

Since it has no specific distance from the model, the intensity
of a directional light does not diminish as it travels through
space.  Generally, therefore, directional lights appear brighter
than point lights of equal intensity.  

Use the text boxes in the Directional Light Geometry box to
specify angles for Bearing and Altitude. 

Bearing sets the horizontal angle, which is measured in the x-y
plane counter-clockwise from the positive x-axis (or "3
o'clock" in the Bearing diagram).  The vertical angle, or
Altitude, is measured up (0ø to 90ø) or down (0ø to -90ø) from
the x-y plane.  Zero degrees is at 3 o'clock on the Altitude
diagram.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\The Sun
The sun is a special directional light.  Locate the sun by
entering the appropriate latitude, site orientation (north
angle), day of year, and time of day.  BIG D uses this
information to calculate the exact
bearing and altitude of the sun. 

The North Angle is a horizontal angle which points toward true
north, relative to the coordinates used in your model.  The angle
is measured in the x-y plane counter-clockwise from the positive
x-axis of the model.  For example, if true north is in the
positive y direction in your model, the north angle should be set
to 90ø in BIG D.

Use the Latitude slide bar or text box to specify your location
on earth relative to the equator.  Latitude is measured as an
angle from -90ø to +90ø.  A positive latitude (0ø to +90ø) is
used in the northern hemisphere and a negative latitude (0ø to -
90ø) is used in the southern hemisphere.  Keep a large world
map on hand to look up latitudes (or a globe is more fun,
because you can spin it).

Specify the month of the year and the day of the month to tell
BIG D the time of the year you want to see the sun.  BIG D
uses this information to determine the tilt of the earth relative
to the sun.  Pick the Month scroll list, locate the cursor over
the month you want, and release the pick button.  Enter the
day of the month in the Day slide bar or text box.

The hour and minute of the day set the exact position of the
sun, and are based on military time.  When setting the hour,
use 1-23 hours.  Four o'clock PM is 16 hours and 00 minutes,
for example, and one minute before midnight is 23 hours and
59 minutes.  One minute after midnight is 00 hours and 01
minutes.

The hour and minute are based on true solar time.  That is, the
sun's bearing will be due south (in the northern hemisphere)
at exactly 12 noon.  Keep in mind that local time will usually
vary somewhat from true solar time.  You may also need to
adjust for Daylight Savings Time.

Adjust the sun's color with the Hue, Saturation, and Value  (or
RGB) slide bars or text box, just as you would any other light. 
(Science fiction illustrators can have fun with this one.)  A
colored sun simulates sunlight which is filtered through the
atmosphere.  For example, an orange hue can emulate the
setting sun.  Typical Brightness values for the sun range from
1 to 3.

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Exiting Add Light
There are four ways to get out of the Add Light dialog box:
[OK], [Cancel], [Previous Light], and [Add New Light].
Picking [OK] confirms your changes.  Picking [Cancel] aborts
any changes you have made.  After you pick either [OK] or
[Cancel], the Edit Light dialog box appears on the screen, just
in case you might want to do some more editing.  Pick [Done]
to return to the main menu bar.  

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Light Summary
Assign Materials and define a View before you start working
with Lights.  Then specify Lighting Options: Ambient Light,
Background, Fading and Fog.  Remember that reflective
objects in your rendering will be affected by the Background
color, e.g., a reflective gold object may look green if you use
a blue background.

Keep the color of Point, Spot, and Directional lights close to
neutral (or slightly orange for incandescent, slightly blue for
neon) unless you're setting up a special effect.

The more lights you use, the less intensity you need per light. 
You will probably have to go back and adjust the lights after
you do a preliminary rendering.  Use as few lights as possible
to light the scene, in order to reduce shadow confusion and
rendering time.  Use X-ray lights to boost brightness and
lighten shadows in specific areas that need them, often behind
objects facing the main light source.

Locate Point and Spot lights by either typing in coordinates
or moving the icons in the viewports.  Directional lights and
the Sun must be located with their respective Geometry dialog
boxes.  

<SEE ALSO>
Light Summary
Lights Menu Overview
Add Light Dialog Box
Define a Light Procedure
Directional Lights
Light Geometry
Point Lights
Spot Lights
The Sun
X-Ray Lights
Delete a Light Procedure
Edit a Light Procedure
Background
Lighting Options Procedures
Ambient Light
Exiting Add Light


\Views Menu Overview
To define a view in BIG D, you specify a location for the
Camera, and a location for the Target.  The camera is the point
from which you wish to view the model.  The target is the
point toward which you look.  Where you position the camera
and target determines how the final rendering will look, as if
your eye were the camera, and what you see when you look
toward the target is the "snapshot" of the final rendering.

The Views menu lists only three options: Add View, Delete
View, and Edit View.  (You must define at least one view of
a model before you can generate an image.) 

BIG D supplies three procedures for locating the camera and
target: dragging the icons in the viewports; typing in x, y, and
z coordinates; and using the Tools menu down the right side
of your screen. 

When you use the Files menu to first load a scene, the Top
and Front viewports appear on the right side of your screen. 
As soon as you pick an option from the Views menu, a third
viewport appears in the lower left corner of the screen, and the
camera and target icons appear in the Top and Front viewports.
The wireframe models in the Top and Front viewports always
show isometric (parallel) views - top, front, back, right, etc. 

The purpose of these viewports is to show the location of the
camera and target in relation to the model, and to let you
graphically change the camera and target locations.  
The lower left viewport is an entirely different matter.  In this
viewport, what you see is what you get - in the rendering.

The wireframe model in the lower left viewport changes its
position (shrinks, swells, tilts, rotates, scoots right or left)
as you enter view settings, drag the icons, or play with the
Tools.  The position of the wireframe model in this viewport will
be the position of the model in the rendering.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box


\Define a View Procedure
1.  Pick [Views] from the main menu bar, and [Add View]
from the pull-down menu.  When you select [Add View], the
third viewport will appear in the lower left corner of the
screen.  

2.  The Add View dialog box will appear with the title "View
#1."  The text box labeled "Name:" will show a default view
name consisting of the first four letters of the current BDS
file, combined with a four-digit number, in this case, "0001."
Example: file0001.  Leave the "Name:" space alone unless you
can't stand the default name.  

3.  Leave the button labeled "View active" toggled ON. 

4.  In the Options group box, use the scroll list button labeled
"Projection:" to choose either Perspective or Parallel
projection.  "Perspective" is the default.

5.  Use the text box labeled "Lens:" to change the lens focal
length of the camera, if you need to.  The default is 35. 

6.  Leave "Twist angle:" at its default of zero, for now.

7.  Locate the Camera and Target.  The 3-D viewport in the
lower left corner of the screen changes to show your adjust-
ments.  There are three different methods you can use:

7-A.  In the Camera and Target group boxes, pick the text boxes
labeled x, and then type in coordinates, pressing [Enter] after
each x, y, and z have been entered. 

7-B.  Using the mouse, pick the Target icon (a small square
with an "X" inside) in a viewport, hold down the pick button,
and drag it into a new position. Then select the Camera icon
(a "box" camera, literally) and position it.  Use the Top
viewport to position the icons in relation to the x-y plane, and
the Front viewport to position the icons vertically.

7-C.  Use the Tools menu icons (down the right side of the
screen) to position the Camera and Target in increments, pan
the camera and target in relation to the model, adjust twist
angle and lens focal length, and control zoom functions.

8.  When you are satisfied with the view shown in the lower
left viewport, exit the Add View dialog box by picking the
[OK] button.  The [Cancel] button erases any changes you
made.  If you have defined more than one view, picking [OK]
or [Cancel] calls up the Edit View dialog box, which lists all
Views defined of a model.  Pick [Done] on the Edit View
dialog box to return to the main menu.

9.  Pick [Add New View] on the Add View dialog box if you
wish to go directly to a fresh Add View dialog box to define
another view.  When you have defined more than one view,
picking [Previous View] sends you back to the Add View
dialog box for the previous view.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Delete a View Procedure
1.  Pick [Views] from the main menu, and [Delete View] from
the pull-down menu.

2.  If you have defined only one view, a screen will appear
that asks, "Are you sure you want to delete this view?  View
#1 - 1."  Pick the [Yes] button (or the [No] button, if you
change your mind).

3.  If you have defined more than one view, picking [Delete
View] calls up the Delete View dialog box, which contains a
scroll box listing all the views you have defined of the model.

4.  Pick the view you wish to delete (it will highlight in the
scroll box) and press the [Delete View] button.  Press the
[Done] button if you want to keep the view after all.

5.  When you press [Delete View] the "Are you sure you want
to delete this view?" screen appears.  Pick [Yes].
<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Edit a View Procedure
1.  Pick [Views] from the main menu, and [Edit View] from
the pull-down menu.

2.  If you have defined only one view, the Add View dialog
box for that view reappears.  Use the same procedures to edit
the view that you used to originally define the view.  Pick
[OK].  If you have defined more than one view, the Edit View
dialog box will appear for any last minute editing.  Pick
[Done] on the Edit View dialog box to return to the main
menu.

3.  If you have defined more than one view, picking [Edit
View] calls up the Edit View dialog box, which contains a scroll
box listing all the defined views of the model.

4.  Pick the view you wish to edit (it will highlight in the
scroll box) and press the [Edit View] button.  The Add View
dialog box for that view will appear.  Make the changes you
need and press [OK].

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Active Views
When you choose a BDS (scene/model) file to render, BIG D
will render every view you ever defined of that
model, even if some of the views have already been
rendered - unless you use the View Active operation to
deactivate some of the views.

For example, suppose you have defined five views of a house
you're rendering.  Yesterday, you did the finished renderings
of Views 1 and 2.  You played around with it some more
today; Views 3 and 4 are okay, and View 5 is spectacular. 
You're pressed for time, and you only need a rendering of
View 5.  BIG D will render all five views unless you toggle
View Active OFF for Views 1, 2, 3, and 4.

1.  Pick [Views] from the main menu, and [Edit View] from
the pull-down menu.

2.  The Edit View dialog box displays a scroll list of the views
defined of the BDS file.  To the right of each view file name
is a View Active toggle button.  Pick the buttons to turn off
the views you don't want rendered.  The toggle button contains
a black square if it is ON.  If the button is blank, it's toggled
OFF.

3.  When you have finished with the toggle buttons, pick the
[Done] button to return to the main menu.

4.  If you want to look at a view before you toggle it off,
select the view name in the scroll box, and pick the [Edit
View] button.  A dialog box for that view will appear, and if
you still want to deactivate it, toggle off the [View Active]
button on the dialog box.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\View Name
You may want to render several views of the same model -
for a walkthrough sequence, for an animation, or just to
experiment.  Each separate rendering of a model has its own
file name.  BIG D assigns each view/rendering a default file
name, which uses the first four letters of the BDS file name
and a four-digit number, e.g. logo0001.

You can assign a name of your own choice by picking the
"Name:" text box, typing in a name, and pressing [Enter]. 
Make a note of each view you define, and its file name.

File Names

From the time you load a model and scene, until the moment you
view the final image, the current file assumes several aliases.  

Suppose you want to make several renderings of an apartment
building.  (The economy has picked up, and multifamily
projects have revived.)  The DXF file comes into BIG D with
the name "mlfm9208".  Load the DXF model file
(mlfm9208.dxf) and the BDS prototype scene file (bigd.bds);
the resulting model/scene file gets a new name (say,
apartmnt.bds).  Actually, you can name it anything -
godzilla.bds.  

Usually, the next step is to set rendering variables and assign
materials using the Options menu.  You don't have to worry
about file names at this point.  BIG D assigns your operations
to whatever BDS file is the current file (the last one loaded.)

When you get ready to define views, the Add View dialog box
appears with a default name, apar0001, for the first view -
the first four letters of the BDS file (apartmnt.BDS) and a
four-digit number.  Subsequent views are named apar0002,
apar0003, etc.

Next, define the lights.  The Add Light dialog box comes up
for the first light with apar0001 as the default name for the
light.  Yes, this is the light name, not the view name.  Light
names and view names use the same form - first four letters
of the BDS file plus four-digit number - but don't worry; 
they stay in different places and don't get themselves mixed
up. 

When you have assigned materials and rendering variables, and
defined lights and views, you're ready to render.  The Render
Scenes dialog box lists scenes to render under the BDS name,
so you'll pick the file listed as apartmnt.bds.

Once BIG D has rendered the image (or images), use the Show
Image dialog box to view it.  The listings in the Show Image
scroll box revert to the View name plus an Image File Type
extension, so you'll see apar0001.gif, apar0002.gif, etc., and
you can pick the particular view you wish to see.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Views and Lights
You can define only one set of lights for each BDS scene/-
model file.  Suppose you have set up one view of a model, and
defined the lights for that view.

Next, you define another view of the same model from another
angle.  You might want to shift the lights a little bit, or do
one daytime and one nighttime rendering.  The changes you make 
in the lights for the second view will also change the lights in
the first view.

To get more than one lighting setup for the same model, you
must create a separate BDS file.  Simply go back to the Files
menu, and type in a new name for the BDS scene/model file. 
The new BDS file will retain the materials and rendering
variables you've already specified.  Use the new BDS file to
define a new view with a different lighting setup.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Projection
Use the Projection scroll list button to specify parallel or
perspective projection.  In a parallel projection, edges which
are parallel in the 3D model are parallel in the generated view. 
The Top and Front viewports show parallel projections. 
Parallel projections include plans, elevations, and isometric
views.  

A perspective projection gives a more realistic representation
of the 3D model.  Edges parallel in the model converge toward
"vanishing points" in perspective.
<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Twist Angle
The Twist Angle option enables you to generate scenes that
show the model tilted up to the left or right. (Either for artsy
effects, or to simulate the view from a banking airplane.)

If an invisible wire were stretched from the camera to the
target, Twist Angle would rotate the camera about the axis of
the wire.  The Twist Angle setting determines the degree of tilt
added to the scene.  A twist angle of 90ø turns the model on
its side; 180ø turns it upside down.

The angle of twist is measured counter-clockwise from the
positive x-axis of the camera, not the x-axis of the model. 
Since the camera is being twisted instead of the model, tilting
the camera up on the right causes the model to appear to tilt
up on the left.  The default setting for Twist angle is 0ø.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Entering Coordinates
When you import a DXF model file, the model's coordinates
come into BIG D with it.  The origin - 0,0,0 - in the model
will be 0,0,0 in the BIG D rendering.  In many modeling
programs, the origin is in the lower left corner of the x-y
plane, or "ground" plane, which is also the ground plane in
BIG D's Top viewport.

In the Camera and Target group boxes, enter a coordinate for
each axis by picking the appropriate text box and typing in a
number, and pressing [Enter].  The default unit of linear
measurement is inches. 

You can change the default unit, either during installation, or
by using the Display dialog box on the Options menu.

Dragging the Icons

The camera icon is a small "camera".  The target icon is a
square with an "X" inside.  The camera icon is connected to
the target icon by a line.  For the first view that you define of
a model, the camera icon with have a number "1" beside it. 
The camera icon for a second view of the same model will be
labeled "2", and so on.

The Top viewport displays the location of the camera relative
to the x-y plane, and the Front viewport displays the camera's
height, or its position relative to the z axis.

To move an icon, position the cursor over the icon and press
the pick button.  Hold down the button, and drag the end of
the view line to a new location.  When you release the pick
button, the icon will jump to the new location.  The text box
x, y, and z coordinates will change to specify the new position. 

\Tools Menu
The column of symbols down the right side of your screen is
used for fine-tuning the view, and other arcane operations.

Most Tools operations require that you activate a specific
viewport by picking any spot within that viewport.  
Operations that change the orientation of the model relative to
the borders of the Top or Front viewport may or may not
change the final rendering.  Operations that change the
orientation of the model in the lower left viewport will change
the view in the rendering.

If you get the camera icon so far from the model that it
disappears off the edge of the viewport, you can retrieve your
camera by using the Zoom Out symbol.  Zoom out far enough so that
the camera is included in the viewport. Then use the mouse to
drag the camera closer to the model, and Zoom Extents to restore
the model to its original size.

If you get hopelessly snarled up experimenting, press [Cancel]
to abort your changes, and [Done] on the Edit Views dialog
box, to return to the main menu.  Pick [Views] and then [Add
View] to get back to Add View dialog box.

Adjusting the Target

At the top of the Tools menu is a bull's eye with eight
directional arrows, which adjusts the location of the target. 
Each arrow will rotate the location of the target around the
camera location.  You must activate the lower left viewport to
use the Target symbol.

Picking the up arrow will rotate the target upward about the
camera.  This causes your center of view to move upward (the
model appears to move downward).  When you select the right
arrow, the model will appear to move to the left.  This might 
be upsetting, because it appears to be the opposite of what
should happen.  Keep in mind that it is the target (where
you're looking) that is moving, not the model.

The other arrows move the target in their respective directions. 
If you pick the head of the arrow, the target moves at a larger
increment than if you pick the tail.

Adjusting the Camera

The camera symbol is a little camera surrounded by eight 
arrows.  Pick the arrows to rotate the camera a small amount
around the target.  Selecting the up arrow (for example) will
rotate the camera upward about the target.  This enables you
to view the model from a higher elevation.  Picking the head of
the arrow moves the camera in larger increments than picking the
tail does.  You must activate the lower left viewport to use the
Target. 

Twist Angle

The three-quarter circles with arrowheads adjust the twist angle
of the camera.  Picking the clockwise - circle vector on the
left twists the camera clockwise around an imaginary line from
the camera to the target.  (Remember - this will make the
model appear to twist counterclockwise.)  Picking the counter-
clockwise vector does the opposite.

To use the Twist Angle operation, you must first pick the
lower left viewport, since its orientation is a line from camera
to target.  

Pan

The Pan icon is a plus with arrowheads on ends of each arm,
surrounded by eight more arrows.  "Pan" moves both camera and
target, but keeps them in the same position relative to each
other. 

Selecting the right Pan arrow causes both the camera and
target to move to the right.  This causes the model to slide to
the left, relative to the screen, but keeping the same orienta-
tion.  The other arrows move the camera and target in their
respective directions.  

If you activate the Top or Front viewport, you can use Pan to
change the position of the model in the viewport.  However,
you must activate the lower left viewport to make Pan affect
the final rendering.

Zoom
The Zoom In symbol consists of two arrows pointing toward
each other.  Picking Zoom In moves the camera closer to the
target while maintaining the same orientation. 

Picking the Zoom Out symbol - the two arrows pointing
away from each other - steps the camera back from the
target, and makes the model smaller in relation to the size of
the viewport.

Zooms only affect the final rendering if you activate the lower
left viewport.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box
Show Lights
Show Views
Tools Menu
Vector Pan Procedure
Zoom Extents
Zoom Previous


\Lens Focal Length
Lens (or lens focal length) controls how wide a view of the
model is generated.  Lens settings are measured in millimeters,
and range from 5mm to 1000mm.

Low settings specify a short focal length, which produces a
wide angle view, similar to a wide angle lens.  The model is
smaller in relation to the size of the frame.

High settings specify a long focal length, which produces a
narrow angle view, similar to a telephoto lens.  The model is
larger in relation to the size of the frame.

The Lens default setting is 35, which produces an angle similar
to the normal human cone of vision.  The lens focal length, in
effect, sets the position of the top, bottom, and side borders of
the scene.

Increasing the lens focal length is similar to using the Zoom In
operation.  However, using a high Lens setting will cause the
model to appear bigger in the screen without causing the
increased perspective distortion that would occur if the camera
were zoomed in to increase the model size.

To set the lens focal length, pick the text box, type in the
desired value, and press [Enter].                           

The two magnifying glasses (Tools Menu) can be used to adjust the camera's
lens focal length.

The glass with the plus sign increases the lens setting, which
makes the model appear larger - similar to using a telephoto
lens.  The glass with the minus sign lowers the lens focal length
setting, which makes the model appear smaller in relation to
the viewport, similar to using a wide-angle lens.  (Plus =
bigger model, minus = smaller model.)  Default setting is 35.

You can use the Lens symbols to change the lens focal length
in any activated viewport, but only the lower left viewport will
change lens focal length in the rendering, and in the "Lens:"
text box.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Zoom Window Procedure
The mountain range symbol below the magnifying glasses
enlarges a portion of the model by zooming the camera into a
window within a viewport.
To create a Zoom Window:

1. Activate one of the three viewports by picking any point
within the viewport.

2. Pick the Zoom Window symbol.

3. Pick a location in the activated viewport for one corner of
the Zoom Window, and hold down the pick button.

4. Move the mouse in a diagonal direction to "drag open" a
window.  (The window then expands from your first point.)

5. When you're satisfied with the window's size and location,
release the pick button.  The area within the window will
expand to fill the viewport.

6. To get rid of the zoom window, pick the Zoom Extents
button (the cube symbol) to the right of the Zoom Window
symbol.

You can zoom a window in any activated port, but only the
lower left port affects the rendering.

<SEE ALSO>
Show Lights
Show Views
Tools Menu
Vector Pan Procedure
Zoom Extents
Zoom Previous


\Zoom Extents
The cube symbol is also a special case of zooming.  Picking Zoom
Extents automatically zooms the camera so that the border of the
viewports is at the outermost points of the model.  

If the model is wider than it is high, the extreme left and right
points will define the position of the edge of the viewport.  If
the model is taller than it is wide, the highest and lowest
points set the borders.  The model retains its proportions and
orientation toward the camera.

If you have defined a "base" or a "backdrop" for a model,
Zoom Extents will enlarge to include all of these planes, but
will not necessarily extend far enough to include the camera.
You can use Zoom Extents on any activated viewport, but only
the lower left viewport will affect the final rendering.

<SEE ALSO>
Show Lights
Show Views
Tools Menu
Vector Pan Procedure
Zoom Extents
Zoom Previous

\Vector Pan Procedure
The Vector Pan symbol is a right-leaning arrow.  You can use
Vector Pan to slide the model along a line in any direction.

1. Activate one of the three viewports, and then pick the
Vector Pan symbol.

2. Press the pick button to choose a start point in the viewport.
Holding down the pick button, drag the cursor to the end
position you want, and release the button.

3. The model will move in the direction of the line, for a
distance equal to the length of the line.
Vector Pan can be used in any activated viewport, but only the
lower left viewport affects the rendering.

<SEE ALSO>
Show Lights
Show Views
Tools Menu
Vector Pan Procedure
Zoom Extents
Zoom Previous


\Zoom Previous
The U-turning arrow is Zoom Previous, and allows you to
"reset" the Zoom to the previous setting.

<SEE ALSO>
Show Lights
Show Views
Tools Menu
Vector Pan Procedure
Zoom Extents
Zoom Previous


\Show Views
Normally, if you are not using the Views menu, the view icons
- camera and target - are not visible in the Top and Front
viewports.  If you're using another menu and need to see the
icons, pick the Show Views symbol, which is the left-looking
eyeball at the bottom of the Tools menu.  Pick the symbol
again to get rid of the icons.

<SEE ALSO>
Show Lights
Show Views
Tools Menu
Vector Pan Procedure
Zoom Extents
Zoom Previous


\Show Lights
The small light bulb is the Show Lights symbol.  If you are
using a menu other than Lights, pick the Show Lights symbol
to display Point and Spot light icons in the Top and Front
viewports.

<SEE ALSO>
Show Lights
Show Views
Tools Menu
Vector Pan Procedure
Zoom Extents
Zoom Previous


\Adjusting the Viewports
Each viewport has a small button in the upper right corner, and
another one in the upper left corner.  Picking the upper right
button expands that viewport to fill the screen.  Pick the button
again to shrink the viewport back to normal size.

Pick the button in the upper left corner of the viewport to call
up a scroll list of view points - Top, Bottom, Left, Right,
Front, Back.  If you pick "Right", for example, the wireframe
model in that particular viewport will rotate to display the
right side.  Although the model will move, relative to your point
of view, the camera and target icons will remain in the same
position relative to the model.

Once you have the new view - as shown in the lower left
viewport - defined to your liking, select the [OK] button to
save the view.  Select [Cancel] to abort your changes.  

<SEE ALSO>
Show Lights
Show Views
Tools Menu
Vector Pan Procedure
Zoom Extents
Zoom Previous


\Exit Add View Dialog Box
If you want to define another view without returning to the
main menu, pick [Add New View] to call up a fresh Add
View dialog box.  It will be titled "View #2" and the "Name:"
text box will contain the new name, e.g. "logo0002".  If you
have defined more than one view, pick [Previous View] to go
directly back to earlier views.

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Views Summary
You may render a view of a model from any angle, using
either parallel or perspective projection.  Define a view by
specifying a location for camera and target, Lens focal length
(default 35), and Twist angle (default 0.)
BIG D will generate an image file (rendering) for every view
you define of a BDS file unless you toggle off unwanted views
with the View Active button.  BIG D will assign a default
name to each view.

Camera and target may be located by typing in x, y, and z
coordinates, by dragging the icons in the viewports, and by
using the Tools menu.  You must activate a viewport to use
most Tools.

Adjusting Lens focal length is similar to changing the focus of
an actual camera, and changes the size of the model relative to
the size of the viewport frame.

Twist Angle rotates the camera around the axis of a line
between camera and target.                                       

<SEE ALSO>
Adjusting the Viewports
Active Views
Ports
Projection
View Name
Views Menu Overview
Views Summary
Views and Lights
Define a View Procedure
Lens Focal Length
Delete a View Procedure
Edit a View Procedure
Twist Angle
Exit Add View Dialog Box

\Render Menu Overview
The Render menu provides only two options: [Render Scenes]
and [Show Image].  Render Scenes renders a chosen scene file
photorealistically.  Scene files consist of a model, materials,
and scene settings (camera, lights, and rendering variables), all
saved in a .BDS file.  Render Scene uses the largest share of BIG
D's processing time.

The second option, [Show Image], simply calls up and shows you a
file saved in a .GIF, .PCX, .WIN, or .TGA (TARGA) format.  Of
course, any files in these formats can also be viewed with Show
Image.

<SEE ALSO>
Render Menu Overview
Render Scene Procedure
Render Scenes Dialog Box
Rendering Options
Rendering a Group of Files
Show Image Procedure


\Render Scene Procedure
Use the Render Menu to render the current .BDS Scene File
The current scene file is the last file you loaded during a
session.  The Render Scenes dialog box appears with the
current scene file listed in the text box labelled "Name."  

1.  Pick [Render] from the main menu-bar and [Render
Scene] from the pull-down menu.

2.  Pick the [Render] button on the Render Scenes dialog box. 
BIG D will generate an image file for each of the views you
have defined of a scene.  (See "Views" section.)

NOTE: If you made changes to the scene settings (e.g., moved
camera, changed light settings, etc.), a dialog box will ask if
you want to save the scene file.  Pick [Yes] if you want the
changes to be saved, or [No] if the changes are temporary.

Render Several Scenes at a Time

1.  Pick [Render] from the main menu-bar and [Render Scenes] from
the pull-down menu.

2.  Check the current directory listed next to the label "Direc-
tory:".  Use the Directories scroll box if you need to retrieve
scene files from other directories.

3.  Pick one of the scene files you want to render from the
Files scroll box, then click on the [Add scene] button to add
it to the scene list ("Scenes to render" scroll box).  Repeat
this for each scene file you want to render.
4.  Pick the [Render] button to start the rendering process.

NOTE: Rendering may take minutes or hours depending on the
number of views defined per scene file, rendering settings,
complexity of the model, and how many scenes you have
decided to render.  

Re-rendering a scene (after the initial rendering) may take the
same amount of time, OR less time, depending on the changes
you made to the scene.  If possible, BIG D re-uses parts of the
previous rendering, thus speeding subsequent renderings
considerably.  

<SEE ALSO>
Render Menu Overview
Render Scene Procedure
Render Scenes Dialog Box
Rendering Options
Rendering a Group of Files
Show Image Procedure


\Show Image Procedure
1.  Pick [Render] from the main menu-bar.

2.  Pick [Show Image] to call up the dialog box.

3.  Check the current directory.  Use the Directory scroll box
if you need to change directories.

4.  Check the file type (listed next to the label "Type:").  GIF
is the default file type.  

To change the file type, position cursor over the file type
shown, then pick and hold to display a scroll list of the other
file types - TGA, PCX, and WIN.  Release the mouse button
over the desired file type.

5.  Use the Files scroll box; click on the file you wish to view.

6.  Pick [Show Image].  BIG D will display the rendering on
the monitor, probably shocking you senseless.

7.  When you've finished staring at the rendering, hit [Esc] to
return to the Show Image dialog box. 

<SEE ALSO>
Render Menu Overview
Render Scene Procedure
Render Scenes Dialog Box
Rendering Options
Rendering a Group of Files
Show Image Procedure


\Render Scenes Dialog Box
The Render Scenes option is used to create (the final) image
files.  BIG D generates image files in one of four formats:
TGA, PCX, WIN, or GIF.  (Use the Options-Image File dialog
box to set file type).

At the top of the Render Scenes dialog box is the button
labelled Render Options, which comes up with a default of
"Render to Screen".   This directs BIG D to render the scene
to the screen, as you might expect.  The other option is "Text 
Only," which renders with only a status-box on your screen,
reporting progress of the rendering.  The status-box will
change its place from top to bottom of the screen, to avoid
"burning in" the image.  The status-box specifies that you may
abort the rendering with the [Esc] key.

If you choose the Rendering Option "Render to Screen", BIG
D will first give you a status-box, so that you can see how to
abort the rendering, and then your screen will go black.  An
8X8 block of pixels will now paint the rendered picture, first
to the right, and then to the left.  Choosing "Render to Screen"
allows you to see the image as it "develops," and abort
immediately if the settings aren't right.

You can render the current scene, or render a whole list of
scenes from files you put into the "Scenes to render" scroll
box.

<SEE ALSO>
Render Menu Overview
Render Scene Procedure
Render Scenes Dialog Box
Rendering Options
Rendering a Group of Files
Show Image Procedure


\Rendering a Group of Files
The rendering of a group of files takes place as a batch-
process, which means lining up a group of scenes you want
rendered one after another, just like a bunch of people standing
in line at a savings-and-loan, waiting to throw away their
money.  The program renders the group of files you select
without bothering you, once you've set the process in motion. 
Batch processing can be done overnight to keep from tying up
the computer during peak use times, or tying yourself up
during your own peak use time.

Add scenes to the "Scenes to render" list by selecting a scene
file from the Files scroll box, and then picking the [Add
Scene] button.   Delete scenes by picking a scene from the
"Scenes to render" scroll box, and then picking the [Delete
Scene] button.

<SEE ALSO>
Render Menu Overview
Render Scene Procedure
Render Scenes Dialog Box
Rendering Options
Rendering a Group of Files
Show Image Procedure


\Show Image Dialog Box
The Show Image option is used to look at existing image files -
usually the last step in the rendering cycle.  

Use this option to view preliminary renderings (so
you can fine-tune settings), and to view the finished products. 

<SEE ALSO>
Render Menu Overview
Render Scene Procedure
Render Scenes Dialog Box
Rendering Options
Rendering a Group of Files
Show Image Procedure


\Using Autocad
Before you can render a model, you must create the model.  Use
AutoCAD or other modeling software to create the model, and save
it in DXF format (in AutoCAD, use the DXFOUT command).  BIG D
recognizes both ASCII and binary DXF file formats.

Supported Entities

BIG D supports the following 3D entities:
*3D faces
*3D polygon meshes (3D surfaces made up of 3- or 4- sided faces)
*3D extruded entities (in AutoCAD, objects with a thickness)
*surfaces of revolution
*blocks
*closed shapes made up of lines, arcs, or polylines
*circles
BIG D also recognizes layering and coordinate system information.

Layers

After loading a model into BIG D (Open DXF option), you must
assign materials to the various layers.  When building the model,
be sure to set up the layers so that the layers are organized by
material.  For example, you might have a "concrete" layer
containing all the objects made out of concrete. 

Coordinate System Data

BIG D uses the coordinate system information associated with each
entity in your drawing.  If you use AutoCAD's local coordinate
systems (UCS command) to build the various parts of a model, keep
all the edges of a surface on the same coordinate system -
don't switch coordinate systems in the middle of a 3D entity.

Extruded Entities

BIG D recognizes AutoCAD extruded objects.  If you draw a square,
for example, and then assign a thickness to the square, BIG D
will treat the object as a rectangular prism.  Using extruded
entities simplifies the modeling process, and keeps the file size
to a minimum. 

To see how this works, load (DXFIN command in AutoCAD) the sample
model named house.dxf (bigd\acadsup\ subdirectory) into your
modeling program, and then examine the entities that make up the
model. You'll notice that the majority of objects making up this
model are simple extruded shapes, and that the entities are
layered by material.

Closed Shapes

Closed shapes, such as circles and polygons, are treated by BIG D
as surfaces.  Any closed shape will be treated as a surface if
the shape was drawn on a single coordinate system, and if the
shape is "perfectly" closed. Within each shape, the endpoints of
arcs, lines, and other entities must match, and have the same
layer, elevation, thickness, and coordinate system.

You can create a hole in a surface by placing a closed shape
within another closed shape. Again, the layer, elevation,
thickness, and coordinate system must match for the two
shapes.

This simplified modeling technique will speed up the modeling
process and keep the file size manageable.

Surfaces of Revolution

Although BIG D recognizes 3D polygon meshes created by AutoCAD's
REVSURF command, BIG D also supplies a LISP routine you can use
within AutoCAD.  The BDRSURF routine makes surfaces of revolution
handled more efficiently by BIG D.

Follow the steps listed below to use this routine:

1.  Copy the BDRSURF.LSP file from the ACADSUP subdirectory to
the AutoCAD subdirectory.
Change directory to the autocad subdirectory (example: CD\ACAD
[Enter]).  Assuming that the BIG D work directory is named
"bigd6", type:

copy C:\bigd6\acadsup\*.*[Enter]

2.  To load the routine, you must first load AutoCAD; then at the
command prompt, type:
(load "bdrsurf")[Enter]

3.  Draw an axis line parallel to the Y axis.

4.  Draw the profile of the surface of revolution using arcs,
lines, or polylines.  The profile should be on the right side of
the axis line.

5.  Type BDRSURF [Enter] to run the routine.

6.  Enter a block name (maximum 31 characters).

7.  Pick the end of the axis line as the insertion point.

8.  Enter the included angle (usually 360ø for a closed figure).

9.  Pick the entities that make up the profile of the surface of
revolution.

10.  Use the INSERT command to insert the newly created block.
Pick the insertion point, and enter scale factors and rotation
for the block.

11.  Use the DXFOUT command to export the model to BIG D.


Other Modeling Software

BIG D was originally designed to be used with models created by
AutoCAD, but you can load models created by other modeling
programs.  Regardless of the source, all models must be in DXF
format.

Try loading various 3D entities from your modeling program to
verify compatibility.

\File Formats Overview
File formats used by BIG D can be divided into 3 categories: 3-D
model files, BIG D program files, and image files (renderings).  

3-D Model Files

3-D model files must be in DXF format to be used by BIG D.  The
DXF file format, first used by AutoCAD, has become one of the
standard file formats used to transfer drawings and 3-D models
from one CADD system to another.  BIG D extracts the layer
settings, block names, and model coordinates from the DXF file.  
DXF is a "vector" file format created by Autodesk, Inc.

BIG D Program Files

Listed below are a number of files you will access (knowingly or
unknowingly) as you ork with BIG D:

BDS files (files with a .bds extension) are scene files created
when you save a scene using the Files menu.  Scene files are
ordinary text files containing the settings for camera, lights,
layer/material assignments and other rendering variables 
You should copy important BDS files to floppy disk. 

BDE files are graphic entity files containing the geometric
description of the model. BDE files are compiled from the DXF
model file when you use the Open DXF option. BDE
files are saved in binary format.

BDM files contain the settings for material properties.  The BIG
D material libraries (example:, bigd.bdm) are stored in the \lib
subdirectory under the BIG D work directory (default name
is \bigd6).  If you make changes to a particular material (by
selecting Options-Materials), BIG D will create a backup of the
old material file assigning a BDK extension to the backup.

SCR files are text files containing rendering instructions that
run BIG D in batch mode. SCR files are normally created by BIG D
but you can use a text editor to create your own scripts. 

User-generated scripts can be used to create a series of related
renderings, for example: a walk-through of a building.

LOG files are generated when you render a scene.  The LOG file
contains elapsed time and other rendering stats. Because it is a
text file, you can examine a LOG file using the DOS "TYPE"
command, or you can load it into a text editor.  You can print
out BDS and LOG files to document scene settings and rendering
stats.

ERR files are generated if the program encounters an error.  You
should examine the ERR file and print it out before calling for
technical support.

BDSHOW Utility

BDSHOW.EXE is a program used to view renderings outside of BIG D.

Simply type BDSHOW followed by the image file name and extension
(example: BDSHOW HOUSE.GIF [Enter]).  To create a slide show,
make a batch file containing a command line for each image file
(see example below).

(batch file name SHOW.BAT)
BDSHOW HOUSE1.GIF
BDSHOW HOUSE2.GIF
BDSHOW HOUSE3.GIF
BDSHOW HOUSE4.GIF

To make your slide show portable, copy the image files to a
floppy disk along with the bdsetup.exe and bdshow.exe files.
To display the slides on another system:

1.  Copy the files over to the hard drive.

2.  Run the BDSETUP utility to configure the "Rendering device"
(match to installed display card).

3.  Type the name of the batch file (example: SHOW [Enter]).

Image Files

Image files are the end product of the rendering - generated when
you use the Render Scene option.  You can generate renderings in
GIF, TGA, WIN, and PCX formats.  If you plan to transfer or view
the image file with another program, you will have to choose the
image file type supported by the other program.

Image files contain a pixel by pixel representation of the screen
image - numbers in the file represent the color of each pixel on
the screen.  For high resolution settings, the image file can be
very large.  (Image files are ordinarily found in formats using
compression methods to reduce file size.)

Note that BIG D's Show Image feature supports only 8 bit, 256
color GIF and PCX image files.  TGA image files may be 8, 16, 24,
or 32 bit, however.

Image File Types

BIG D supports the following image file types (listed by file
extension):

GIF is the default BIG D image file type.  BIG D supports 8
bit/256 color GIF files, only.  GIF is a Compuserve graphics
format designed to provide color image file interchange across a
variety of hardware and software platforms. GIF files use
Lempel-Ziv-Welch compression to reduce file size. A number of
conversion/manipulation utilities are available for GIF files.

TGA (TARGA) is the file format originally used by Truevision high
resolution graphics boards.  TARGA files provide a standard file
format for true-color images at high resolution.  If you have a
card/monitor capable of displaying more than 256 colors, you
can specify 16, 24, and 32 bit modes for TARGA files.  They may
be uncompressed or use run-length encoding.  (Some software does
not recognize compressed TGA files.)

WIN is a TGA file with a different extension.  You can use these
formats interchangeably (simply rename the file).

PCX is a Zsoft image file format used by PC Paintbrush and
Publisher's Paintbrush.  PCX files are 8 bit image files (they
have a maximum of 256 colors), which use run-length encoding as
their means of compression.

SCR or Script Files

SCR or script files (.scr extension) can be used to run BIGD in
"batch mode" to generate a series of renderings.  You can set up
a script file to:

*  render several different scene files without having to load
each scene through the BIGD interface.  For example, you can
render a series of models overnight.

*  render several image files from a single scene file without
changing the original settings for the scene - for example,
several test renderings (test1.gif, test2.gif, test3.gif,
etc.) with different settings for ambient light.

The following procedures describe how to create a script file
with examples of applications.  

Use a text editor or word-processor to create a script file and
save the script file as an unformatted text file (ASCII file)
with an .scr extension.

Suppose you wanted to do two renderings from two different scene
files.  We'll use the sample scene files logo.bds and house.bds,
that came with the program.

1.  Load your text editor or word processor and type in the
following commands:

scene logo.bds
perspective on
camera 28,-60,25
target 0,0,4
lens 50
fullshade -r logo1
scene house.bds
perspective on
camera
target
lens
fullshade -r house1

Save the file as loghouse.scr (be sure to save from a
word-processor as plain ASCII text).

The first line loads the scene file named logo.bds.  The next 4
lines set up a particular view.  You must include camera and
target settings in the script file for each scene to be
rendered.  The fullshade command (fifth line) is the command that
starts the rendering process and generates the image file
(logo1.gif).  The -r directs the rendering to the
screen.  Leaving off the -r would direct the rendering to file
only (i.e., text mode rendering).  Ex: fullshade house1  (as the
last line of the script above).

2.  The next example illustrates how to set up a script file to
render several variations of a single scene. 
The listing below will render logo.bds with two different
settings for ambient light intensity.  Using your text editor,
type in the following commands:

scene logo.bds
perspective on
camera 28,-60,25
target 0,0,4
lens 50
ambientintensity 3
fullshade -r ambient3
ambientintensity 4
fullshade -r ambient4
To run your script files:
from the DOS-prompt in the BIG D directory, type:

C:\>bigd  -sfilename[Enter]

without typing the .scr extension on the filename.

In general, script files contain the same command syntax as a
scene file.  Script files may contain any combination of commands
as long as at least one view (camera and target settings) is
defined within the script file.  Lights, lighting options,
layer-material assignments, and image file settings can all be
set with a script file.  The only variables that cannot be set
from a script file are the material properties/texture/bump
variables.
