Editing Solids and Surfaces - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 199

The SHOWHIST variable specifies if component objects are displayed even if we don't
select them with the Ctrl key. With value 2 , component objects are always displayed;
with value 1 , it depends on individual properties; with value 0 , they are never dis-
played.
Note
The need for changing components is rare. Normally we don't maintain history
records, thus decreasing memory consumption.
The BREP command
The BREP command (no alias) allows removing history records and edition through
grips or the PROPERTIES palette for the objects to be selected. It only prompts for
the selection of composite solids, solid primitives, or solids obtained from linear ob-
jects.
All selected solids become generic 3D solids.
Exercise 7.1
We are completing the house initiated in Chapter 4 , Creating Solids and Surfaces
from 2D .