Creating a brush entity

Brush entities are built from brushes and utilize their geometrical volume or physical features (i.e. for an area to effect or for a button). They include things such as triggers, conveyor belts, and rain.

How to create a Brush Entity

1. Create a new world brush.
2. Select it in one of the 2D views.
3. Use the shortcut key Ctrl+T (or, from the right-click menu, choose "Tie to Entity", or click the toEntity button in the bottom right panel.)
4. Select the type of brush entity to create from the Class list.
5. Click Apply.

The standard for every brush entity is defined in the actual game's settings, but it is usually func_detail, which is solid for everything.

For a list of current HL2 Brush Entities see the Category: Brush Entities