11 Exercise 1: Creating a Sphere and a Cube

	The first thing you will do in this exercise is get familiar with the Amapi 3D user-interface. To make this as easy as possible, we suggest you choose the Workshop interface (see chapter User Manual/Preferences/ Interface).
The work space and the interface. 1. When Amapi starts up, it displays the table and the grid. They are provided to help you orient yourself in space.
2. Depending on the interface you selected (see the interface description in the chapter User Manual/Preferences/Interface/Tool palettes), there are two possibilities: Þ If you selected the Workshop interface you will see the Construction Palette displayed on the right-hand side. Move the mouse to the far right, as if you wanted the cursor to leave the screen. You will see the Modeling Palette. Do it again: the Assembly Palette appears. Repeat this process a few of times: the various tool palettes are displayed one after another. Return to the Construction Palette. Þ If you selected the Standard interface, on the left-hand side you will see a floating palette that you can move around.
Selecting a unit system
Choose “centimeters” in the “Preferences/Units” menu.
Building a sphere 1. In the Construction Palette click on the Sphere tool icon to select it. Two axes appear; since the scene is empty, their origin is at the center of the table. If an object is already in the scene, you can set the origin yourself. 2. To facilitate object creation and modification, you can increase or decrease the step size along the axes. To do so · Press the “+” or “–” keys of the numeric keypad. · Click on the icons of the Assistant Palette.
3. Creation of the sphere: Þ A first click in the scene will define the base of your sphere. Þ Next, move the mouse upward: the sphere is being created and is growing larger as the mouse moves upward. Þ At the same time, you will see a window at the bottom left corner of the screen. It is the Data Window; it displays the sphere’s radius. This value is modified in real time as you move the mouse. Try to set a radius of approximately 15 cm. Þ Then click. You have just created a sphere!
Þ A “+/-” Tuner is then displayed. It indicates that you can modify the number of sections defining the sphere: · Click on the icons of the Assistant Palette (at the top of the screen). · Press the “+” or “-” of the numeric keypad.
Þ Press the “-” key three or four times: you can see the sphere being modified in real time. The number of sections defining the sphere is displayed at the bottom left corner of the screen. Þ Press the “+” key a couple of times. Do not add too many points! (Smoothing an object increases its complexity and memory requirements. It is better to smooth an object with the appropriate tool once the modeling is done.) For this example, set the number of sections to 8 or 9.
4. Quit the Sphere tool. This can be done in two ways. We will put the tool aside: Þ If you have chosen the Workshop interface, move the cursor outside the right side of the Amapi window and then back in to put the tool aside. The Tools Palette reappears. Þ If you have chosen the Standard interface, selecting another tool will automatically quit the previous one. Go to the next paragraph.

Building a cube.
1. Drag the cursor on top of the sphere icon in the Construction Palette to open the 3D Primitives Palette. 2. Click on the Cube tool icon to select it:
3. Again you will see the axes being displayed. This time you can set their origin using the mouse. This creates a frame of reference to help you create your cube. Click, for instance, near the bottom of the sphere. The origin of the axes is automatically set to the nearest point in the scene.
4. Building the cube: Þ Set the center of the base of the cube. Þ Move the mouse: the cube’s size changes as you move the mouse.
You are now going to enter precise dimensions: Þ Press the Tab key. (This command indicates that you want to enter numeric values. It is accessible in most tools.) Þ The cursor switches to a hand; it confirms that you now can enter a numeric value in the window displayed at the bottom left corner of the scene. Þ Type a value for the X axis, for instance, 10. (Be careful not to press the Return key, as this would validate and end the unfinished entry.)
Þ Press the Tab key again to enter a value for the Y axis, 15, for instance. (Be careful not to press the Return key, as this would validate and end the unfinished entry.) Þ Press the Tab key once more to enter a value for the Z axis, 20, for instance. Þ Press the Return key to validate. The cube is created. Validation automatically quits the Cube tool. You now have a scene made up of a sphere and a cube.

Changing the viewpoint.
1. You can rotate around the scene using the arrow keys of the keyboard. This will change the viewpoint accordingly. Holding down an arrow key will rotate the viewpoint continuously.
2. Let us now zoom in on the scene. Þ Press the “3” key of the numeric keypad a couple of times; we are getting closer to the object. Þ Zoom out using the “.” Key. Þ Click on the icon in the Control Panel to zoom in on a detail of the scene. (You could also use the hotkey “1” on the numeric keypad.) A white rectangle is displayed. This is the zooming window. Click on a point to set it, the top of the sphere for instance. This point will be the center of your new view. Move the mouse to define the size of the window. Click to validate the operation. Þ Click on the icon in the Control Panel, or press the “0” key of the numeric keypad to view the entire scene.
3. You can switch planes to change the viewpoint. This is also done through the numeric keypad: Þ Press the “5” key to go to top view. Þ Press the “4” key to go to left view. Þ Press the “6” key to go to right view. Þ Press the “8” key to go to rear view. Þ Press the “2” key to come back to the front view.
Rendering the scene You now know how to navigate in Amapi 3D virtual space. To visualize a rendered view of your scene, press the Return key.

You can move around your scene once your objects have been built. However, you can also move around your scene while your objects are being created. Do the exercise again, but move around the scene as you build the sphere and the cube. Try, for instance, to set the origin of the cube on the side of the sphere.