Ok, for my map I need a big, round tower, in which you can walk. So meshes are not an option. I tried to create it out of an arbitrary brush… but it has to have at least 24 sides. A value below this, and the tower looks like sh*t. Well, I mean you can actually see the corners = not good. 24 sides would be just perfect. I am this far:

But it would be a pain in the ass to cut the brushes to the right shape, so they don’t overlap. I’m stuck… 
I hope somebody can give me some hints, or a nice little prefab (but this should be the final solution…) 

