[ODE] odd contact behavior -- no bounce for heavy objects?
jk at spiderland.org
Mon May 23 11:15:40 MST 2005
I'm experiencing some odd behavior with large bouncing objects.
If I let a sphere of radius .5/density 1.0 to drop from a height of
20 with a coefficient of restitution of 1.0, I get a totally elastic
collision and the sphere goes back to (or relatively close to, at
The problem is that if I set the density to 100 (or if I make a
change in radius resulting in a similar mass) there is almost
no bounce at all. This can be seen in test_boxstack by setting
the contact bounce parameter to 1.0, bounce_vel to 0.0, and then
creating spheres of radius 1 with density 100.
I realize that the masses of such objects are going to be quite
high, but my understanding of how the coefficient of restitution
should work is that mass should not matter -- the kinetic energy
should be preserved and the sphere should bounce up with
approximately the same velocity it came down with.
Can anybody shed any light on this? Is this a bug, or is there
something wrong with my understanding of how the collision
- jon klein
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