Uneven ground/floors

I'm sure there's a tutorial out there somewhere for this, but I can't seem to find it...

I just want to know how to create a floor/ground brush that is not perfectly even. My level is mostly in a city, but I want some pitted dirt/snowy/sloped paths that aren't just flat. The best I can come up with is rudimentary shapes using the vertex and clipping tools to carve out or create segments for potholes and rocks (I do the carving manually, without using the carve tool since that just crashes Hammer anytime I use it), and that sometimes also leads to errors. My level's looking very much like some beta Half-Life mod map circa last century.

If anyone could help, it'd be greatly appreciated.

u need to use displacements. there are a number of tutorials on how to use create them. the basics can be found here

[Intraman]

What you're looking for is to make a displaced brush. Look around for some tutorials on how to make them. They can be quite tricky.

[wisemx]

Displacements?
http://www.sdknuts.net/akg/?sdk=tutdisp

Thanks all, that's just what I needed.