[ODE] Re : Triangle Mesh Creation Time.

[Gonçalo Lopes]

Hi there,

I'm interested in this problem myself. Me and my team are using ODE to
integrate dynamic interaction in real-time with image processing data
and we had the same issues. We got along quite well with dynamically
creating trimeshes every image frame, but these were low triangle
count trimeshes.

The ideal solution, one would think, would be to create just one
single trimesh, but then to allow dynamic manipulation of its
vertexes? Would this be feasible with the current trimesh
implementation?

Also, another important question for dynamic interaction is how to
correctly set up parameters on the ODE side so that the newly created
entities really behave like continuous objects, and not like
instantaneously created geometries. We've achieved this by hammering
the derived velocities for each frame into the ODE bodies, but maybe
this is not recommended.

Does anyone here has any experience with setting up dynamically
created interactions with ODE? I feel that the need to incorporate
this is rising, given the increase in the augmented reality and
real-time physical user interaction trends.

Best regards,

Gonçalo


On 6/12/07, Patrick Enoch <Hendrix_ at gmx.net> wrote:
> Did I miss something? Why not create one trimesh?
>
>
> On 12.06.2007, at 14:37, Frédéric Brachfogel wrote:
>
> > Hello,
> >
> >
> > Implementing dynamic trimesh  collision is a simple solution to the
> > problem of long data structure creation time ;)
> >
> > Concerning the contact points, I found a simili answer in the
> > documentation, but I have to be sure. Here is the sentence :
> > "
> > The convention is that if body 1 is moved along the normal vector
> > by a distance depth (or equivalently
> >
> > if body 2 is moved the same distance in the opposite direction)
> > then the contact depth will be reduced to
> >
> > zero. This means that the normal vector points "in" to body 1.
> >
> > "
> >
> > Is that true that with the contact point array filled by the user
> > function, ODE perform the dynamic physic changes on the body ? It
> > really seems to be the case, but I have to be sure too.
> >
> > Moreover, in the case of a point patch (contact along surfaces), do
> > the Depth be devided by the number of points in the patch ?
> >
> >
> > F.Brachfogel
> >
> > --------------------------------------
> > Chronophage Games
> > 3-5 rue Lashermes
> > 43000 Le Puy en Velay
> > FRANCE
> >
> >
> > > Date: Tue, 12 Jun 2007 08:13:07 +0200
> > > From: jsinecky at tiscali.cz
> > > To: fred3d2 at hotmail.com
> > > CC: ode at ode.org
> > > Subject: Re: [ODE] Triangle Mesh Creation Time.
> > >
> > > Hi,
> > >
> > > Frédéric Brachfogel wrote:
> > > > Anyone for this no ? Is my question clear ?
> > > >
> > > > Thank you,
> > > >
> > > >
> > > > F.Brachfogel
> > > >
> > > > --------------------------------------
> > > > Chronophage Games
> > > > 3-5 rue Lashermes
> > > > 43000 Le Puy en Velay
> > > > FRANCE
> > > >
> > > >
> > > >
> > ----------------------------------------------------------------------
> > --
> > > > From: fred3d2 at hotmail.com
> > > > To: fred3d2 at hotmail.com
> > > > Subject: RE: [ODE] Triangle Mesh Creation Time.
> > > > Date: Sat, 9 Jun 2007 14:11:31 +0000
> > > >
> > > >
> > > >
> > > > Thank you for reply.
> > > >
> > > > A simple solution for me is to use custom collision class (?).
> > > >
> > > This is not clear to me .... do you think implementing dynamic
> > trimesh
> > > collision on your own is a simple solution?
> > > >
> > > >
> > > > I have a question about this :
> > > >
> > > > The user collision function fills a contact data array.
> > > > How will the engine (ODE) perform the pose changes on the
> > > > geom to simulate the contact so that there is no
> > > > inter-penetrations ? In other terms, how must I fill the
> > > > contact data ? In the case of patch ?
> > > >
> > > This is covered in ODE documentation, try to search it for
> > > "dContactGeom". Or even better, read it through before going on with
> > > some serious ODE development.
> > > >
> > > >
> > > > F.Brachfogel
> > > >
> > > > --------------------------------------
> > > > Chronophage Games
> > > > 3-5 rue Lashermes
> > > > 43000 Le Puy en Velay
> > > > FRANCE
> >
> >
> > http://www.windowslive.fr/hotmail/default.asp Windows Live Hotmail
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>
>
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