Thank you, that seems to be exactly what I need.

In case anyone is wondering, the object I am trying to model is responsible for the whip cracking/banging type sound that is heard from the wingtip vortices just after the aircraft has flown over. The scientists do not even know about this object so I am trying to recreate it to show everyone. I have officially called it an "ENDPLUG" - single word.

I want to be able to bounce objects inside a cylinder. I want gravity to be zero so that the objects can continue to bounce around.

It would be nice if the objects could rotate around as well.

This is important to demonstrate a how a previously unknown object looks inside a wingtip vortex - wake turbulence. Any ideas?

TIA