These are some videos of physics tests in 3D. The tests are not pre-rendered, and run with the Bullet physics engine under Panda3D.

‘Physics shapes’ are often different to the shapes you see on the screen — they are a more ‘optimised’ version to give a smoother simulation, but are slightly less accurate. These are some of the fastest physics shapes, combined with some slower ones. Adjustments are made to the environment every frame, to produce a ‘gravity well’:

After a while, the objects ‘collect’ in the centre:

If you leave it long enough, and have enough objects, you produce a galaxy-like arrangement of orbiting objects!

Note that this software was written for my previous employer, which means I do not hold the licence, and cannot sell it myself.