[ODE] contact joints / attaching them

[gl]

> > Yeah, but the amount of penetration determines the force.  And the
amount
> > will be different with different timesteps - ie. the timestep is
relevant to
> > the collision results indirectly.
>
> Yes, what you say is completely true... but it does not have any bearing
> on the Flavien's (correct) assertion that collision detection functions
> are completely independent of the timestep.

Agreed - the _functions_ are independent.  But the collision _results_
aren't.

> The CD code only computes the penetration depth, and it doesn't need
> timestep information to do that

Indeed, but the timestep determines how far an object was moved and thus the
amount of resulting penetration - so the collision _results_ (and thus the
physics simulation) are affected by the timestep.

So let's say you run collision detection on a fast moving object twice
during each physics step, as was suggested.  This means that when a
collision is detected (the good part), it will penetrate less than all other
objects in the simulation, given the same parameters - and thus the results
will be a little different.  At least that's how it seems to me.  It may not
make much difference - but then again it may.
--
gl