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# Solid Edit: Alter Torus

This tutorial illustrates the application of the SOL EDIT state to the torus solid.

Figure (est-top): Top View of a Torus

`mged> size 6
mged> in tor tor
Enter X, Y, Z of vertex: 0 0 0
Enter X, Y, Z of normal vector: 0 1 0
Enter radius 1: 1
Enter radius 2: 0.2
mged>`

Figure (est-top) is the display of the torus solid in viewing state. Since the Z-axis is perpendicular to the viewing screen, a view of all sides cannot be seen.

Figure (est-sed): The Torus in Solid Edit State

`mged> Twist ROTY knob clockwise and restore
mged> Twist ROTX knob counter-clockwise and restore
mged>`

These actions generate a view of the torus that shows all sides, as shown in Figure (est-sed) .

`mged> Select the ``Solid Illum'' entry in the button menu
mged> Move the mouse out of the menu area
mged> Click the mouse to enter SOL EDIT state
mged>`

The torus is a ring whose cross-section is a circle. The distance from the vertex to the center of the cross-section is r1 and r2 is the radius of the circular cross section.

Let the points I and O be the intersection of the line x=-z and the torus. Then,

    I = (-(r2-r1) cos 45, 0, (r2-r1) cos 45 )
    O = (-(r2+r1) cos 45, 0, (r2+r1) cos 45 )

- Translate Operation
- Rotate Operation
- Scale Operation
- Scale Radius 1 Command
- Scale Radius 2 Command