3D Primitives and Conversions - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 155

Primitive surfaces
In the previous chapter, we explained how to create surfaces from linear objects with
the EXTRUDE , REVOLVE , SWEEP , or LOFT commands. Here we present a command
to create rectangular surfaces or delimited by planar objects.
Creating planar surfaces
Here is a command to create planar surfaces.
The PLANESURF command
The PLANESURF command (no alias) creates planar surfaces defined by two opposite
corners or delimited by one or more existing objects.
By default, the command just prompts for two opposite corners and creates a rectan-
gular surface:
Command: PLANESURF
Specify first corner or [Object] <Object>: Point
Specify other corner: Point
The command has only one option, Object .