import walls/floorplan into map

[Frogulis]

Also, as Robtics said above, if your facility has multiple levels, an engine that supports multiple levels and properly three-dimensional maps (as opposed to the semi-faked 3D of the Cube (what AssaultCube uses) engine) would be better for your purposes. The Cube 2 engine and Sauerbraten would do this, although it doesn't have the realistic theme that AssaultCube does.