Large & Small Collision Shapes and Large Mass Ratios

[JonathanILevi]

On page 35 of the Bullet SDK Manual it recommends "Avoid very small and very large collision shapes" and "Avoid large mass ratios (differences)". Both of which are exactly what I want to do!

I want (not quite real sized) orbiting planets in a dynamic world mixed with bullets. And ships docking on large moving stations. And no, static stations and planets is not a solution (okay, planets could probably be kinematic bodies...).

Should I be looking at a different Physics Engine? Any recommendations?

[drleviathan]

If you have small satellites interacting with large planets using a weak coupling like gravity then you should be fine. However, if you were making dynamic piles of planets crushing small satellites between them using hard RigidBody collisions then you would have problems. Similarly, a few small ships landing on a large station should work, but smashing small ships between large stations would be problematic.

It would probably be ok to smash a small ship against one large station using another small ship: you'll have to try it. As you increase the mass of the smasher relative to the smashee, while keeping the mass of the large station high, you will eventually discover what kinds of problems arise.