[ODE] timestep

[Russ Smith]

> Is there any harm in using variable times for the worldstep?

in theory there shouldn't be, in practice there is one small problem. if
you take a small step then follow it by a much larger step then then any
error-correcting velocity that was applied to the bodies in the first step
will be extrapolated into a much larger velocity in the second step,
potentially causing bodies to 'pop' away from each other. this problem has
been on my list of things to fix for a while - i have a fix that should
work well but will take time to implement (the underlying cause of the
problem is rather subtle).

russ.

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