Func detail

func_detail is an internal brush entity that does not affect visibility or cause other brushes to be sliced - in other words that does not affect the structure of the rest of the map. It should be used on all brushwork that does not form the 'backbone' of a map (and that is not already tied to an entity).

A world brush (left) and a detail brush. The blue lines are visleaf boundaries, where the world has been chopped up, leading to longer compile times and lower performance.

Valve provide an example map at sourcesdk_content\hl2\mapsrc\sdk_func_detail.vmf. You can also load up the HL2 map sources and hide detail brushes with their auto visgroup to see where Valve used them.

Caveats

• Detail brushes cannot be used to seal a map.
• Because detail brushes do not slice other brushes, light can seep underneath them if the other surface's lightmap scale is larger than the detail brush is wide/tall. If you encounter this, manually create a slice in the underlying brush (Shift+X).
  • This effect can cause detail brushes with lots of surface contact to become inefficient, because the surface beneath them is being rendered too!
• Surfaces on very thin (about 2 units thick) detail brushes have been known to disappear at certain distances. As a workaround, use func_brush instead.
• Brushes with translucent materials applied will automatically become detail.

Good candidates

• Pillars, plinths and supports
• Free-standing walls
• Suspended walkways
• Stairs (create a smooth wedge-shaped brush underneath)
• Small buildings
• Rotated brushes

See also

(These duping pages should really be merged into this one.)

• Controlling Geometry Visibility and Compile Times - Detail brushes
• See also BSP Map Optimization - Detail Brushes
• See also Optimization (Geometry) - Detail brushes

Keyvalues

(You'll probably never need to change these.)

• Template:Kv dxlevelchoice