I have a metal pipe model and now I want it to break when hit by a rock. I have the rock covered and know how to make it collide with the pipe. I just need to know how to realistically make parts of the pipe bend up like in a pipe break. Any help would be appreciated.
You could probably get some pretty good results using a stiff cloth simulation to stand in for the metal.
You could also handle it manually with blendshapes, joints, etc. You'll have to do more work, but it will also afford you more control.
If you go the cloth route, I recommend against making your full-res pipe into the cloth object. Instead, use a lower-res version--without thickness in its walls--as the deformable cloth object, then use a Wrap deformer to have it move the high-res object around.