Editing and Visualizing 3D Solids - Mastering AutoCAD for Mac - page 614

The three Boolean operations are as follows:
Intersection Uses only the intersecting region of two objects to define a solid shape
Subtraction Uses one object to cut out a shape in another
Union Joins two primitives so they act as one object

The fourth option, interference , lets you find exactly where two or more solids coincide in
space—similar to the results of a union. The main difference between interference and union
is that interference enables you to keep the original solid shapes, whereas union discards the
original solids, leaving only their combined form. With interference, you can have AutoCAD
either show you the shape of the coincident space or create a solid based on the shape of the
coincident space.
Joined primitives are called composite solids. You can join primitives to primitives, compos-
ite solids to primitives, and composite solids to other composite solids.
Now let's look at how you can use these concepts to create models in AutoCAD.

FIGURE 22.1
Creating a tube
by using solid
modeling

Create two cylinder primitives,
one for the outside diameter
and one for the inside diameter.

Cylinder for
inside diameter

Cylinder for
outside diameter

Superimpose the cylinder
for the inside diameter onto
the cylinder for the outside
diameter.

Use the Subtract command
to subtract the inside
diameter cylinder from
the outside diameter cylinder.