Stormz shows how to quickly make a pile of debris and rubble using bullet dynamics in Houdini.

One thing that just screams tedium is placing objects into a pile. Let’s say you want to have a pile of garbage, debris, or rubble. It might take a while to move everything you need into place. An alternative is to create a simple simulation to handle that kind of randomness for you. 

An easy way to do this is with the Bullet Solver. This latest tutorial from Stormz shows how you can use the Bullet Solver in Houdini to simulate a debris pile rather than placing all the stuff manually.