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Getting Started with 3D-Filmstrip

The main steps in using the program are:

1) Choose a Category to work with.

When the program starts up, the Surfaces category is chosen by default. However, you can change to a different category by selecting it from Category menu. As soon as you have chosen a new category, the first menu to the right of the Edit Menu changes to the name of that category, and we will refer to it as the Main menu;so that when the program starts up, the Main menu is the Surfaces menu, but as soon as you choose say Planar Curves from the Category menu then the Main menu becomes the Planar Curves menu.

 

2) Choose a particular object from the Main menu.

For example, if the current category is Surfaces, you might choose Paraboloid, Hyperboloid, Monkey Saddle, Whitney Umbrella, etc., or an item from one the several submenus of the Surface Menu (Non-orientable, Pseudospherical, Minimal). This will produce a default view of this object. Instead of choosing one of these pre-programmed objects you can, for most categories, also choose User Defined... from the Main menu, which will bring up a dialog permiting you to enter formulas describing some other object of the category. You can then click OK to get a default view of the object described by your formulas, and then go on to set various parameters and viewing options as described below. But if you hold down the Option key as you select an object, you will be spared waiting for the default view to be drawn, and can go right to setting these parameters and options. At any point, selecting Create from the Action menu will cause the program to redraw the current object with the current choices of parameters and options.

 

3) Optionally, use the Settings menu.

This will permit you to change (from their default values) various parameters that determine the shape of the object, its resolution and scale, etc. (These are explained in more detail elsewhere.) Curves and surfaces can be specified in a number of different ways, but one of the primary ways is "parametrically", as certain functions of a variable t for curves and of variables u,v for surfaces. Another item in the Settings menu brings up a dialog that permits the user to set the minimum and maximum values of these variables. For the differential equations categories there is a Settings menu item that allows the user to set the initial conditions and length of time for which the solution will be traced, and also the step-size that will be used in the Runge-Kutta algorithm that computes the solution.

The Custom... item of the Set Light Sources submenu of the Settings menu brings up one of the more complex dialogs of the program. This lets the user set the color of the five light sources (Source0, Source1, Source2, Source3, and AmbientSource) and the direction of the light rays from Source1, Source2, Source3. The two parameters that determine the how shiny a surface is (SpecularExponent and SpecularRatio) are also set using this dialog. When SpecularRatio is zero the surface has a matte appearance, and when it is one the surface is mirror-like (see Phong Shading for details). This dialog is also used in combination with the Set Coloration submenu of the Action menu to determine the color of a surface when the Color item of the View menu is chosen. See the documentation on Color for more details.

There is a Set Monitor submenu of the Settings menu to set the number of available colors. This has the same functionality as the Monitors Control Panel, but it is preferable to use this menu since the program will know immediately about the change you make and take steps to optimize for the new setting, but if you should use the Monitors Control Panel then the program will figure it out after a while, and do the right thing. Any change made using the Set Monitors menu will be reversed when you quit 3D-Filmstrip. If possible you should use "Thousands of colors" (i.e., 16-bit color). Millions of colors will give only marginally better quality and will require much more memory.

 

At any time, after you have made changes using the Settings menu, you can select Create from the Action menu to see what the selected objects looks like with these modifications.

 

Details of the Settings menu appear elsewhere.

 

4) Optionally, use the Action menu and View menu.

This will permit you to make various choices determining how an object will be displayed. For example, whether a surface will be "oriented" (and if so it's orientation), whether it will have the same or different color on both sides, whether it will be seen in perspective or orthographic projection, whether wire-frame or patches will be used, whether coordinate axes will be displayed, etc. For the ODE categories you can select the items Show Direction Fields and Project ODE Orbits in the View menus to turn these features on and off. You can also choose between a white and a black background in View menu, and if you have a color monitor and in addition the proper red/green (or red/blue) glasses thenyou can instead choose Stereo Vision from the View menu to switch between a normal and a stereo display of a 3D object like a surface, polyhedron, or orbit of a 3D ODE.. If you don't have a pair of these glasses, click here for directions on how to obtain them.)

There are some important differences between the Action, Settings, and View menus. First, choosing an item from the Settings menu usually brings up a dialog that permits the user to alter the values of certain numeric parameters, while the items of the View menu allows the user to choose among a small number of different options. Secondly, making a change using the Settings menu does not result in an immediate redisplay of a selected object while choosing an item from the View menu usually does cause an immediate redisplay unless the option key is pressed while the submenu choice is made. (Depressing the option key will also prevent an object from being drawn when it is chosen from the Main menu. So it is possible to choose a new object and then make various changes using the Action, View and Settings menus before displaying it for the first time. Finally, the Action menu is context sensitive, i.e., ts items are determined just at the moment it is pulled down, depending on the current category, the specifics of the current object, and the other choices that have been made from the View and Settings menu.

 

5) Change the Aspect.

If the object is three-dimensional, you can use the many items in the Aspect menu to change the "aspect parameters" (viewpoint, viewdirection and focal length,...) in various combinations to allow you to see many different views of the object. But there is also a much easier and more convenient way to rotate 3D objects using the mouse, called "Virtual Sphere Mode". See Manipulating 3D Objects for details.

In the Plane Curve Category or the Conformal Map category, if you click and drag then the object in the Graphics Window will follow the mouse around. If you now depress the Shift key and move the cursor up or down then the object gets smaller or larger. Morever, in these two categories, if you hold down Command and then drag out a rectangle in the usual Mac way, then when you release the mouse (with Command still down) your selection rectangle will zoom to the entire window.

WARNING: The last two items of the Aspect menu are called "Look at Origin From..." and "Set Aspect Parameters...". The former is fairly innocuous and behaves more or less as expected. However, do not play with the latter unless you know exactly what you are doing (except perhaps to change the "EyeSeparation" if the stereo effect is exaggerated or insufficient). If you don't understand the way the viewing mechanism works, then changing the Aspect parameters in this way can have surprising and non-intuitive results. If you get in trouble using Set Aspect Parameters..., just re-select the object you are working with in the Main menu to get back to the defaults. For more detail see the Aspect Menu

 

6) Animation.

For those categories where it makes sense, you will be able to choose Morph, Rotate, or Oscillate from the Animate menu to create a "filmstrip" of the object. As soon as the filmstrip is created it will start to play back. To abort the playback either type Escape or Command period, or hold down the mouse button until the end of the filmstrip is reached. (You can also temporarily Pause the playback by holding down the spacebar.)

[Initially the playback speed is as fast as possible, and on a fast machine this may be too fast. The program controls the playback speed by adding a certain number of "ticks" (i.e., sixtieths of a second) between successive frames. To change the playback speed while a filmstrip is being played back, press the right-arrow key to add ticks, or the left arrow key to subtract ticks. During playback, a "status line" is added to the bottom of the graphics window giving the current number of ticks added between frames.]

 

When the playback of a filmstrip is interrupted at a particular frame (by typing Escape or Command period), it can be restarted at the same frame by typing Command P. The Settings menu has an item to permit the user to set the the number of frames in a filmstrip. There is also an item that lets the user change the way an object is deformed during a Morphing filmstrip. These are explained in more detail in the discussion of the Settings menu.

 

As well as this "filmstrip" kind of animation there is also another type called "real-time" animation, and you also choose between them using the Animate menu. For real-time animation each "frame" is created on the fly, as needed. This works fast enough to be quite acceptable on most recent machines, except that for Surfaces in "patch" mode it is a little slow, so the program shifts temporarily to wire-frame display mode during real-time animation of surfaces (unless the caps-lock key is down). While filmstrip animation is capable of higher quality, the advantage that real-time animation has over it is that a filmstrip with more than a few frames requires lots of RAM. (And, you don't have to wait while the program makes up the filmstrip.)

After a filmstrip is created, you can save it as a QuickTime movie by choosing "Save Animation as Movie..." from the File menu. There are several important advantages to doing this. First, a movie can be started up almost instantaneously, (while creating a complicate animation from scratch may take several minutes), and secondly a QuickTime movie can easily be converted to a format that will play on other platforms (Unix and Windows in particular). The main disadvantage is that even a fairly short movie can take several hundred Kb of disk space. Movies can be played back using any of a number of movie player utilities, and there is even a primitive player built in to 3D-Filmstrip (choose Open Movie... from the File menu).

 

Elsewhere you will find a more detailed discussion of animations in 3D-Filmstrip.

 

7) Creating a Grand Tour.

There is also a Grand Tour submenu of the Animate menu. This allows the user to create a custom filmstrip by using the Aspect menu to choose a sequence of different views of a three-dimensional object---essentially "flying around" in the virtual mathematical space that the program creates---and snapping frames as one goes.

The Action Menu has items "About This Category..." and "About This Object..." . The first will bring up a window explaining some mathematical and programming details concerning the current category, and also what facilities are provided by the program to help visualize objects of the category, and how to access these facilities. The second is available whenever a particular pre-programmed object is selected, and brings up a window providing more or less detailed information about that object. At the least this window will show the formulas used by the program to create the object, and thus in particular how the object depends on the nine parameters aa,bb,...,ii.. This is the what is required in order to see how to change the parameters. Eventually further explanatory material will gradually be added explaining features of a particular object makes it of special interest. At present, many of the minimal surfaces already have such detailed About This Object... panels, These were written by Hermann Karcher, an expert in the field.