[ODE] I´m totally unhappy with ODE ... Please Help me

Lode Vanacken lode.vanacken at uhasselt.be
Sat Dec 16 05:46:56 MST 2006

I just recently replaced our collision engine with ODE as a first step to
move towards physics integration. I am also using GIMPACT and I don't 
have any problems at all.

For drawing, what are you drawing? Are you using the ODE geoms or you 
own structure? I would
suggest to draw both, this way you can see if they are aligned or not. I 
had problems with my vertex stride
and so on, I know you have tested it in an example, but to make sure and 
as you are rather desperate I would
try this. Some example code for drawing to get you started:

> for(int j = 0; j < dGeomTriMeshGetTriangleCount(geomObj); j++)
> {
>                 dVector3 p1, p2, p3;
>                 dGeomTriMeshGetTriangle( geomObj, j, &p1, &p2, &p3 );
>                 //DrawTriangle Code
> }


arturapps wrote:

>Hi people: 
>I´m working on a game that doesn´t need Real time physics  but needs
>Trimesh-Trimesh colision Detection . 
>The game is a kind  of spaceship race that takes place on a  quite large
>enviromment composed of trimeshes.
>I´m  experiencing all kind of problems with my collisions : Since false
>collisions , until  missed collisions. Sometimes  the near callback is not
>triggered even if two trimeshes visually collide.
>I examined ODE´s documentation and figured out that  it´s possible to use
>just the colision detection capabilitys of ODE.  So my sojtware does not
>create the "word"  and any body   for physics  processing. The ODE´s "step"
>of simulation is not called.  The software just create the colision space 
>and associate   geoms ( trimeshes ) to  the game entitys . 
>That´s the way the game works: 
>Create collision space
>Create Entytys and associated geoms ( trimeshes) 
>Call Entity´s IA  // Each entity decide about its next movement and then
>modify it´s position and  orientation
>modify entity´s geoms // based on entity´s  position and orientation
>call colision detection (dSpaceCollide) 
> call dcollide  to get contact points between the colision pair
>iinform the entitys associated with the colision geoms , about the colision
>//In the next loop the Entity´s IA will do something as colision response
>Well ... first of all , I´d like to know if is that aproach correct. IS
>there any problem using just colilision detection system  of ode ?
>By the way : I´m using  the version of ODE , that uses GIMPACT instead of
>OPCODE. I downloaded  this version at :
>In second place : I´d like to describe some tests I made to be sure that my
>trimeshes and trimesh creation process are correct: 
>I  changed the test_moving_trimesh example that comes with the  ODE-Gimpact
>project, in order to create the trimeshes from my model file format ,
>instead of creating the "bunnys" on the code.  I didn´t changed the way it
>does trimesh creation because it was the same way I do it . So I could
>notice that my trimesh models work very well . they are displayed correctly
>and collyde very well.  So I discarded problems about vertex order or normal
>In my software I don´t call dGeomTriMeshSetLastTransform in order to update
>temporal coerence for the Geoms. 
>I removed all calls of  dGeomTriMeshSetLastTransform from the
>test_moving_trimesh example  and than I noticed that it does not afect
>colisions , but only the quality of physics simulation. 
>So I don´t know what I can do next  in order to understand my problem ? 
>Help me please !!!

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