2.2 Constructing a cube

In the following example the most important functions are presented and explained:

There are two completely different approaches to get a cube: You can construct it, or you can just set the coordinates of eight vertices. The second possibility is easier for the beginner:

• Generate eight free points by double-right-clicking into the scene.
• Set the coordinates of the points by ’right-click - settings’ on the names of the points in the list or by using the context-menu ?settings?. Use the coordinates (0, 0, 0), (5, 0, 0), (0, 5, 0), (5, 5, 0), (0, 0, 5, (5, 0, 5), (0, 5, 5), (5, 5, 5). Right-click here:

  

  Enter the coordinates and press ok:

  

  It should look like this:

  

  Tip: You can navigate in the dialogue with the TAB-key.

• Alternatively the points can be entered in the command line directly. The input for this would be ’A=(0,0,0)’, ’B=(5,0,0)’ and so on.
• Now you have to construct the sides of the cube. As those are square, you can use the built in parallelogram.¹ Three vertices have to be selected for a parallelogram. The order is important: The middle point is the apex of the angle between the first and the third point. Example: If you select the points in the picture in the order P2, P1, P3, you get the following parallelogram:

  

  If you use the order P1, P2, P3 instead, you get:

  

• The finished cube should look roughly like this:

  

  Now you can brighten up your cube by changing the colors in the parallelograms context menus.

  If the buttons are not hidden (menu Extras - settings - view - show buttons) you can change several colors simultaneously: Select the items you want to change by shift-clicking into the scene and click on the color-button.

  At the same time you can set the objects transparency. This can be done in the context-menu or with the spin-box ’transparency’.

  Alternatively, you can group the sides of the cube (select the sides, choose Extras - Group objects) and adjust the color for the group-object.

  In the end, the cube could look like this: