[ODE] Objects getting stuck with tri-mesh

gl gl at ntlworld.com
Wed Sep 3 08:24:01 2003


> A smaller timestep won't fix it, it will just make it
> less likely to happen. It will also increase the CPU
> work.

I don't think there is a perfect solution, giving the way ODE collisions
work.  I suspect you'll need to tweak all the 'imperfects' until you have
something that works for your app.  Adam's suggestion is worth a try.  You
may also want to write a custom collider primitive for certain things.

Failing all that, you might want to look at a different collision library
and let ODE just resolve the physics.
--
gl

>
> F. Brebion
>
>
> -----Original Message-----
> From: ode-admin@q12.org [mailto:ode-admin@q12.org]On Behalf Of gl
> Sent: Wednesday, September 03, 2003 5:03 AM
> To: Open Dynamics Engine
> Subject: Re: [ODE] Objects getting stuck with tri-mesh
>
>
>
> Well, for one you can use a smaller timestep until you get something
> workable (smaller timestep = less penetration).  Can you not extend the
box
> depth also?
>
> For the ground, another option is to use my dHeightfield contribution.  It
> only supports spheres currently, but it's written so each triangle acts
like
> the planes do - ie. you can penetrate very deep, and it will still kick
you
> out.
>
> I've been trying to talk someone into adding more colliders, but so far no
> luck : ).  I'll need them eventually myself, but I'm busy with other
things
> right now...
> --
> gl
>
> ----- Original Message -----
> From: "Flavien Brebion" <f.brebion@vrcontext.com>
> To: "Open Dynamics Engine" <ode@q12.org>
> Sent: Tuesday, September 02, 2003 2:38 PM
> Subject: [ODE] Objects getting stuck with tri-mesh
>
>
> > I've finally found WHY i get some objects
> > stuck into my scene.
> >
> > It's actually very easy to understand. Check this
> > figure:
> >
> > http://www.fl-tw.com/LightSpeed/stuck.jpg
> >
> > If the object falls "quickly" on a pretty thin
> > box (or any actual thin solid, represented as a
> > tri-mesh), there will be reports of contact
> > points both on the upper and under sides of the
> > box -> contact forces cancel each other (or
> > almost) and the object gets stuck inside the
> > box.
> >
> > Now the question: what's a robust way to fix it?
> >
> > F. Brebion
> >
> > _______________________________________________
> > ODE mailing list
> > ODE@q12.org
> > http://q12.org/mailman/listinfo/ode
> >
> >
>
> _______________________________________________
> ODE mailing list
> ODE@q12.org
> http://q12.org/mailman/listinfo/ode
>
> _______________________________________________
> ODE mailing list
> ODE@q12.org
> http://q12.org/mailman/listinfo/ode
>
>