3D Primitives and Conversions - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 143

Besides the 3D donut shape, where the torus radius is greater than the section radi-
us, this solid primitive can assume two particular shapes:
• Apple shape : The torus radius is smaller than the section radius
• Rugby or American football ball shape : The torus radius is negative
and with the absolute value smaller than the section radius
The options for this command are:
• 3P / 2P / Ttr : We may define the circumference of the torus by three points,
two points on diameter or tangent to two existing objects, and a specified
radius
• Diameter : Instead of defining the radius of the torus, this option allows us
to specify the diameter
• 2Point : The radius of the circle's section can be defined by two points
Exercise 5.3
We are placing some more elements into our cathedral.
1. Open the drawing saved in exercise 5.2 or A3D_05_03.DWG .
2. Create a sphere on top of the highest cylinder, with its center coincident
with the center of the top face and radius 13 (this can also be reached by
a quadrant point). Later we will cut the sphere in half, forming a dome.