[ODE] Universal Joint / Arm -> rotating about its own axis

[Martin C. Martin]

Sure, send away.

- Martin

David Nicolier wrote:
> 
> Hum...the problem is not that they are not always perfectly enforced, it
> won't
> really bother me in this case ;)  but that the legs are doing a 180 or 360
> twist sometime...
> I tried changing the ERP, it doesn't change anything :(
> My sim is running at 50fps, and I'm just moving my character around with
> some
> small forces, and time to time the legs (or arms) are turning around their
> axis
> (I mean in a natural way [->they turn at a slow rate, 1/2 sec for a 180],
> except
> they shouldn't).
> 
> Martin, I can send you a small video (<500K) demonstrating the issue if
> you'd
> like ?
> 
> David
> 
> > Well, ODE doesn't guarantee that joints are always perfectly enforced.
> > Just as a ball and socket can come apart for a little while, or two bodies
> > can interpenetrate for a little while, so the two axes of the universal
> > joint can become non-perpendicular for a little while.  This will be
> > especially true if, e.g. the rag doll is lying on top of its arm.  Does
> > changing the ERP affect the behaviour you're noticing?