[ODE] exploding boxes

[Peter Amstutz]

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This may be a known bug -- box stacking is extremely unstable.

Specifically, I'm looking at the "phystut" program that comes with the
Crystal Space 3D engine.  It uses large, flat boxes for the walls of a
room[1], and the user is able to drop boxes and spheres into the room and
watch them bounce and roll around.  There are several problems:

[1] I expect the answer may be "don't do that" and while that would work
for the outer surfaces of a convex hull, it's useless for building other
things within a space.

The first one is that despite the fact that both the walls and objects
have a bounciness of zero (perfectly inelastic collisions) when an object
is dropped it tends to bounce and roll around a LOT before coming to a
stop...

... almost coming to a stop, that it.  Once the object has almost settled
down, often it will suddenly pop up with a lot of force.  This is clearly
an instability in the integrator, and makes it basically impossible to
stack objects on one another, which should otherwise work fine.

I'd like to see this fixed, and if no one is working on it I would be
willing to give it a shot if someone will point me in the right direction
of where to start in the code.

[   Peter Amstutz   ][ amstutz@cs.umass.edu ][ tetron@interreality.org  ]
[Lead Programmer][Interreality Project][Virtual Reality for the Internet]
[ VOS: Next Generation Internet Communication][ http://interreality.org ]
[ http://interreality.org/~tetron ][ pgpkey:  pgpkeys.mit.edu  18C21DF7 ]
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