Creating 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 Brush Entities see the Category:Brush Entities