EulalieCoevoet / AdaptiveMerging

With adaptive merging we reduce computation time in rigid body simulations.
https://eulaliecoevoet.github.io/AdaptiveMerging/
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basic merging critera based on relative velocity? #22

Closed paulkry closed 4 years ago

paulkry commented 5 years ago

Two issues here... one is my general uncertainty as to using relative velocity as a merging criteria, or if we can't monitor a relative velocity energy. Should probably look like

v^T (J M^{-1} J^T )^{-1} v

Where J maps the two bodies to a combined COM frame, and v has the relative velocities computed in this frame.

Anyway, the other issue is that in watching the spinner, while the linear velocity was what was keeping the bodies from merging, I was surprised to see that the angular velocity had a fairly large mis-match, on the order of 0.01 rad/sec. Perhaps 1000 PGS iterations is not enough? Might be worth another look to see if this kind of innacuracy is expected, perhaps using a spinner with larger blocks?