[ODE] systems flying apart at high angular velocities

[Graham Fyffe]

Hi!  Yes, I think this might help the problem, but maybe not solve it.
 The issue I think will still cause me problems is that it's not a
rigid body.  It's a system with a lot of joints, and I think the
joints are getting pulled apart when I spin it around really fast,
possibly because of the CFM / ERP mechanism.  I wonder if that other
patch that showed up on the list for handling collisions using
iterations could be modified to give me true hard stops, instead of
having to use CFM / ERP close to 0 and 1 to simulate a mostly-hard
stop.  Mabye that's the way to go?  Iteratively satisfy the hard stop
constraints?

- Graham


On 5/25/05, Gary R. Van Sickle <g.r.vansickle at worldnet.att.net> wrote:
> > -----Original Message-----
> > From: ode-bounces at q12.org [mailto:ode-bounces at q12.org] On
> > Behalf Of Graham Fyffe
> > Sent: Tuesday, May 24, 2005 9:04 PM
> > To: ODE Mailing List
> > Subject: [ODE] systems flying apart at high angular velocities
> >
> > Hey everyone.  I've got a joint rig set up for a car
> > suspension, and if I spin the car rather fast angularly, the
> > whole thing flies apart and a few frames later I get NaNs all
> > over the place.
> 
> Sounds like a class-action suit waiting to happen. ;-)
> 
> >  Is there any sensible way to keep a system
> > from flying apart under high velocities?
> >  Thanks.
> >
> > - Graham Fyffe
> 
> By explicitly constraining total system energy.  Somebody (sry, forget who,
> it's in the list archives) has done this on top of ODE for freely-spinning
> rigid bodies to keep them from infinitely "revving up" and detonating, but
> not yet in the general case AFAIK.
> 
> --
> Gary R. Van Sickle
> 
> 
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