Okay. I think someone should make a FULL tutorial on making a fairly advanced map-- with terrain and such. The Badlands2test is a good example of what I'm thinking about. Or, siegecastle or something.
Now, on to the reason. When I try to build any mildly complicated map, the brushes just become unmanagable. Too many on top of each other. Yes, I use groups, but they don't help. Brush based things are just so restrictive...