[ODE] more physics

[Russ Smith]

> looks like another physics engine...
>
> www.tokamakphysics.com

interesting. yet another mention of iterative constraint solving methods
here. the demos are kind of bare bones (i.e., like ODE's bare bones
demos). no mention of the cost.

the box stack demo has an interesting flaw: a nudged stack will tip over,
then freeze part of the way down. this suggests that 'stable' box stacking
is achieved through simply turning off the phisics for a stationary stack
- which is a good idea, but it makes it hard to evaluate the stability of
the underlying method for stacks.

the collision looks like it allows penetration, like ODE. if you collapse
the chain on top of itself it will squish into itself a bit then expand
out.

russ.

--
Russ Smith
http://www.q12.org/