Brush & Geometry

Figured I'd post this because I thought it was a great description of convex geometry:

The Torque Game Engine, like many 3D Engines (Source, Quake Series, Unreal, Etc) works with convex brushes only for level design.

Any concave brush will cause strange visual errors ingame. A brush is convex when a line drawn through it at position will only cross the edge of the brush at two points. A brush is concave when a line drawn through it will cross the edge of the brush more then two times.

This image is an example of a concave brush and how to use multiple brushes to make it convex: Image


Originally taken from: http://www.hl2world.com/wiki/index.php/Tips&Tricks#G