Or you can try doing some Booleans 
The only problem with them is it screws up the mapping where the cut is made, but if you choose the surface and go to Edit Polygons/Texture/Create UV's Based on Camera, it works fine
Darkon
Red bellows of flame have blackened my stones
Convulsing my frame and cracking my bones
Hell's dragons of steel who roar in their chains
Crawl into my caves to suck out my veins.....
-The Mountain P.F.M.