BEPUphysics

Hey norbo, we seem to be having many issues with the cylinder entity type.

They work pretty well when they are rolling on their sides but when they are up-right they have many stability issues and seem to have no friction or roll bounce forever.

My sim has pretty normal settings, with a iteration count of 15 (high accuracy) and a internal timestep of 1/30 i think
Video of the problem here http://www.youtube.com/watch?v=MfwojslftXk (Note it normally happens all the time to every cylinder but when recording my framerate drops heaps and reduces the issue)

That type of behavior isn't entirely unexpected since there exists no 'rolling friction.' The only thing reducing angular momentum when it gets into a dance like that is angular damping. You can try increasing the angular damping of the cylinder a bit to force it to settle down quicker.

Another factor could be the inertia tensor. You could try scaling the local space inertia tensor up or down a little bit to see how it reacts. Going too far either way will introduce different kinds of instability, though.

Increasing the timestep duration to 1/60 seconds could also help, though that would obviously involve doing more updates to cover the same amount of time (which the Xbox wouldn't enjoy). 1/30 seconds is good enough for many simulations but it can be just too long of a timestep for detailed and stable physics in the general case.