%CompileNonSolid
Add this VMT parameter to make brushes non-solid. When compiling the map, VBSP will flag the brush with this material as non-solid. Useful for foliage or light effects.
Unlike a brush tied to a func_illusionary, a worldspawn (or func_detail) brush with %CompileNonSolid does not count as an edict.
Bug:Identical to %CompileNoDraw in 
Left 4 Dead 2.
Confirm: Do all brush faces need to be textured with non-solid materials (like 
content_aux), or will one face being textured properly result in disabling the brush's collision (like 
NOCLIP tool texture)? It might be the former, since Source 1's BSP format is primarily based on Quake II's.
(BSP requires all sides of a brush to either have or not have collision, due to how clipnodes work.)
