Materials and Effects - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 387

Effects
AutoCAD considers, as effects, only scene background and fog or depth cue.
Backgrounds
As scene background, we may automatically apply the sky background (if working
with photometric lighting and perspective) or one of the three options, namely solid
color, color gradient, or image. The VIEW command, presented in Chapter 2 , Visual-
izing 3D Models allows you to specify a background that is associated with the view.
Another way is the BACKGROUND command.
The BACKGROUND command
The BACKGROUND command (no alias) allows you to specify a background for the
current view and next visualizations. The 2D wireframe visual style does not allow
background visualization in the viewport. This command is not available in menus,
toolbars, or ribbon and neither is it documented as a command in Help .