[Command or Variable] rasterizer_wireframe [Default Value] 0 [Valid Values] 0-1 [Description] 
This draws the current world scene including the world model (bsp) and all models such weapons, vehicles, characters and effects in wireframe mode, including non-visible geometry that has collision. This command is extremely useful in determining the placement of visiblity portals, please see the section Level Creationfor more details and information.