2011

You can only subtract regions from other regions that are on the same plane.
However, you can perform simultaneous SUBTRACT actions by selecting sets
of regions on different planes. The program then produces separate subtracted
regions on each plane. Regions for which there are no other selected coplanar
regions are rejected.
You cannot use SUBTRACT with mesh objects. However, if you select a mesh
object, you will be prompted to convert it to a 3D solid or surface.
List of Prompts
The following prompts are displayed.
Select objects (to subtract from) Specifies the 3D solids, surfaces, or regions
to be modified by subtraction.
Select objects (to subtract) Specifies the 3D solids, surfaces, or regions to
subtract.
1012 | Chapter 19 S Commands