Ah, looks interesting... how does it work? :S
There was another TF2 specific function that you apply to a brush to turn the area into 1 big visleaf... here it is... http://developer.valvesoftware.com/...etry_Visibility_and_Compile_Times#Visclusters
^Not really related, but I thought I'd see if anyone was interested
Fyfey
im guessing the Valve mappers arent using this in their maps lol.reducing compile times and BSP filesize dramatically
Orange Box brush entity func_viscluster merges all visleaves inside it into one large leaf, reducing compile times and BSP filesize dramatically. It's exceptionally useful when your map contains open expanses of water or sky, or large, open areas with long sightlines.
A VIS optimisation brush entity. It appears to tell VVIS that all leaves within its volume can see each other. This can greatly reduce the time VVIS takes when compiling a map. It is only useful when used on large, open areas, where large areas of a map can be seen at once.
Even though it reduces compiling time, it does not help to optimise your map. You should attempt to optimise your map first, with proper usage of Func_detail, Hint brushes and areaportals.