Physics, Gravity, and Energy Accumulation

Alpha Omega · Post by **Alpha Omega** » Fri Feb 18, 2011 3:56 am

So I got some weird results working on my physics engine. Video is here.

http://www.youtube.com/watch?v=Vhyir9JiBbc

I am coding with the basic impulse equations (change in momentum impulse). As you can see at the beginning the boxes hit the edge of the cube and fall correctly but then they hit the bottom of the container and accumulate in the same spot and the gravity produces an energy accumulation in the system. How might I go about solving this? I thought I might have to use an energy damper but I still think either the penetration distance is wrong or something its very weird.

Mel · Post by **Mel** » Fri Feb 18, 2011 10:10 am

I'd say the accumulation is working more than it should... i don't know. In Havok, inside 3DSMAX, they use thresholds, and when an object is going to move less than the threshold, the object doesn't move at all, and i guess it also doesn't transfer any energy back to the system.

Alpha Omega · Post by **Alpha Omega** » Fri Feb 18, 2011 11:18 pm

Right now the interpenetration distance is solved every frame instead of holding an old position and reverting back. I tried this but it didnt seem to work very well since I have position updates in too many places. I also made a mistake by not placing the force accumulator as a part of the RigidBody class so simple vector additions could be resolved easily. Maybe this could have something to do with it but I should rewrite the engine from scratch after taking some advanced c++ lessons because I need better consolidation of the code to advance.