I've been learning everything I can about mapping, and I've noticed something. When I make a basic layout, just floors and walls and such, I notice in the game that the wireframe shows everything splitting into a ton of extra polygons. I went through and made most everything into detail brushes, with nodraw on the unseen surfaces, and nodraw world brushes just behind them. In game, there appears to be much less polygons made. The only visible world brushes I make now are the ones I need for good vis leafs. However I notice in a lot of other maps, this isn't done. Is there a reason I don't know about why detail brushes aren't used more?