Func nobuild
Entity Description
A func_nobuild entity will restrict an engineer from building in the specific area it contains.
Availability
This brush-based entity is exclusive to Team Fortress 2.
Normal Use
A func_nobuild area should come in contact with the top side of the brush you don't want the engineer to build upon. The func_nobuild should also be at least 96 units high to keep an engineer from bypassing it by jumping above it.
Ledges
High ledges present an element a bit different from a standard floor surface. If there is a ledge you do not want an engineer to build upon, the func_nobuild area should not only be 96 units above the surface, but 96 units below the surface as well. It should also stick out 96 units from all accessible sides of the ledge. If the ledge is less then 96 units above a larger flat surface, the func_nobuild only needs to touch the top of the surface the ledge is above.
Example Map
An example map demonstrating the entity in use can be downloaded here: http://www.mediafire.com/?vl4dxzxktzf