Brush Last edited 6 years ago2018-06-15 11:28:02 UTC

A brush is a single piece of level geometry within a map. Brushes make up the structure of a map, and are used to describe the areas of a map in which the player will inhabit. A each face of a brush is covered with a texture that define how it will appear to a player.

Brushes, either by themselves or in a group with other brushes, can be tied to an entity to create brush entities.

Brushes can be countless different shapes or sizes, with some rules they must follow:

• Every face of a brush must be perfectly flat.
• A brush must not be concave in any way.
• A brush cannot have any co-planar faces. (That is, faces that lie on the same plane as another face.)
• A brush cannot have any inwardly-facing faces.

Generally speaking, these rules are unlikely to be broken unless more advanced mapping techniques are being used without proper knowledge of how to use them.