[SOLVED] CUDA Collisions

[Jason]

Hi Everyone,

I’m encountering an error when I try to implement collisions using CUDA. I have successfully compiled SOFA and the SofaCUDA plugin from source using the latest commit from the git repository.

In my scene, I drop a humanoid mesh on a floor, and when they contact, I obtain the following error:

ERROR: Element Intersector TTriangleModel<CudaVectorTypes<Vec<3, float>, Vec<3, float>, float> >-TTriangleModel<CudaVectorTypes<Vec<3, float>, Vec<3, float>, float> > NOT FOUND within :

And it then lists several model interaction pairs. I’ve included the scene xml below:

<?xml version=”1.0″?>
<Node name=”root” gravity=”0 -9.81 0″ dt=”0.01″ >
<RequiredPlugin name=”CUDA computing” pluginName=”SofaCUDA” />
<VisualStyle name=”VisualStyle” displayFlags=”showAll” />
<CollisionPipeline name=”Pipeline” />
<BruteForceDetection name=”BruteForceDetection” />
<DefaultContactManager name=”ContactManager” response=”default” />
<CudaProximityIntersection name=”ProximityIntersection” alarmDistance=”0.05″ contactDistance=”0.01″ />

<EulerImplicitSolver name=”cg_odesolver” />
<CGLinearSolver name=”linear solver” iterations=”10″ tolerance=”1e-09″ threshold=”1e-09″/>
<Node name=”Floor”>
<RegularGrid
nx=”20″ ny=”2″ nz=”20″
xmin=”-100″ xmax=”100″
ymin=”-1″ ymax=”0″
zmin=”-100″ zmax=”100″ />
<MechanicalObject template=”CudaVec3f” />
<TTriangleModel template=”CudaVec3f”/>
<Node name=”Visu”>
<OglModel name=”Visual” color=”blue”/>
<IdentityMapping input=”@..” output=”@Visual”/>
</Node>
</Node>
<Node name=”Model” >
<MeshObjLoader name=”modelMesh” filename=”obj/model.obj” />
<MeshTopology src=”@modelMesh” />
<MechanicalObject src=”@modelMesh” name=”Model” template=”CudaVec3f” translation=”0 10 0″ />
<UniformMass totalmass=”50″ />
<TTriangleModel template=”CudaVec3f”/>
<OglModel name=”VisualModel” template=”ExtVec3f” color=”grey” />
<IdentityMapping name=”Mapping” template=”CudaVec3f,ExtVec3f” input=”@.” output=”@VisualModel” />
</Node>

Is there something simple I’m doing wrong?

Thanks so much for your help,

Jason

[François Faure]

Hi, have you tried the available examples ? Do they work ?

[Jason]

Hi Faure,

Yes, the examples work. However, I didn’t find an example that does collisions on the GPU. Did I miss one somewhere?

[François Faure]

Hi,
did you try the examples of the plugin ?
The simplest are:
sofa-dev/applications-dev/plugins/SofaCUDALDI/examples/cube/cube_penality.scn
for a penalty reaction,

and

sofa-dev/applications-dev/plugins/SofaCUDALDI/examples/cube/cube_lilleConstraint.scn
or
sofa-dev/applications-dev/plugins/SofaCUDALDI/examples/cube/cube_LMConstraint.scn
for a constraint-based reaction.

Starting from this, you should be able to create your own scene,
best,
François Faure.

[Jason]

Hi Francois,

I didn’t try those two examples because I couldn’t find them in the git repository. I’m running off of origin/master. Are they in a different branch?

Cheers,

-Jason

[Hugo]

Dear Jason,

The examples are currently available on the git master branch.
It seems strange that you do not have them.

Best,

Hugo

[Jason]

Hi Everyone,

Clearly I am missing something. I don’t find the SofaCUDALDI plugin in the repository at all. I’m using the repository at https://gforge.inria.fr/scm/sofa/sofa.git/ and I don’t find either a sofa-dev or applications-dev directory anywhere in the tree. Where can I find this plugin?

Cheers,

-Jason

[François Faure]

Dear Jason,
Your example does not work because it tries to apply CPU detection on GPU points. To make it work, use Vec3f, instead of CudaVec3f.
SofaCudaLDI is a private plugin, therefore it is not located in the master branch, sorry about the confusion ! As far as I know, there is currently no other implementation of collision detection on the GPU.
Best,

[Guillaume]

Dear Jason,

If you need further information about the SofaCudaLDI plugin, you can let us know. We could provide you the appropriate contact.

Cheers,

Guillaume

[Author]

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