[ODE] Objects getting stuck with tri-mesh

[Royce Mitchell III]

Just out of curiosity, how hard would it be to modify ODE to
dynamically detect extreme velocities, and automatically substep them
down to a logical step size based on the object's gross diameter - or
something?

Wednesday, September 3, 2003, 3:59:27 AM, you wrote:

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

> Extending the box depth: not possible in my case,
> the objects would look unrealistic.

> The dHeightField would fix it, but only for the
> terrain. The problem would still be there for other
> objects on which you can collide (mainly a road, in
> my case).

> 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
>>
>> _______________________________________________
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>> ODE@q12.org
>> http://q12.org/mailman/listinfo/ode
>>
>>

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--
May you always find water and shade,
 Royce3