just a little PSA

When mapping, do NOT clip brushes unless they are tool brushes!
They should NOT overlap! It causes map lag and disorganization.
It may take another 2-3 minutes of compile time, but it will pay off when you don't lag and there is no VIS cutups.

Not saying anyone here does it, just if someone googles "how to map for tf2"
They can stumble apon this little golden tip.

Wait, a minute, what is the best way to make a door (a hole) in a wall?

what do you mean, don't clip brushes?

And another tip, where 2 brushes meet and the player can't see them since they touch, use the no-draw texture on it, since no can see it anyways, no need to render it.

if it is a simple rectangular cut in a brush, just use carve. If it is more complex than that, like a circular hole don't cut, use the vertex tool and morph the brush around a rectangular cut, NEVER cut a circle in a wall, that's a big nono.

What I mean by clip is two brushes overlapping eachother.

And hammer will automaticly nodrsw sides of a brush if it is up against another brush and you can't see that side regaurdless, little time saver.

Also displacements will not protect against leaks so make a brush against them.