Physx slow collision detection

Gaming and Visualization Technologies APIs Physics Modeling (closed)
1

i have created one box and one sphere as actor.
i am applying force to sphere, when force is low collision detection is done properly.
but when the force is high the sphere goes inside the box.

2

Hi,

I think that you need to activate Continuous Collision Detection (CCD). CCD activation depends on ypur physX version.

3

thanks, i have added the ccd code but still my sphere goes inside the box.

InitPhysx()
{
…
gPhysicsSDK->setParameter(NX_CONTINUOUS_CD, bCCDEnabled);
gPhysicsSDK->setParameter(NX_CCD_EPSILON, 0.01);
}

CreateActorBox(float width, float height, float depth, NxVec3 position)
{
…
boxDesc.ccdSkeleton = CreateCCDSkeleton(width*0.8f,gPhysicsSDK);
boxDesc.shapeFlags |= NX_SF_DYNAMIC_DYNAMIC_CCD; // Activate dynamic-dynamic CCD for this body
…
}

CreateActorSphere(float width, float height, float depth, NxVec3 position)
{
…
sphereDesc.ccdSkeleton = CreateCCDSkeleton(2radius0.8f,gPhysicsSDK);
sphereDesc.shapeFlags |= NX_SF_DYNAMIC_DYNAMIC_CCD; // Activate dynamic-dynamic CCD for this body
…
}

NxCCDSkeleton* PhyActor::CreateCCDSkeleton(float size,NxPhysicsSDK* gPhysicsSDK)
{
NxU32 triangles[3 * 12] = {
0,1,3,
0,3,2,
3,7,6,
3,6,2,
1,5,7,
1,7,3,
4,6,7,
4,7,5,
1,0,4,
5,1,4,
4,0,2,
4,2,6
};

NxVec3 points[8];

// Static mesh
points[0].set( size, -size, -size);
points[1].set( size, -size,  size);
points[2].set( size,  size, -size);
points[3].set( size,  size,  size);

points[4].set(-size, -size, -size);
points[5].set(-size, -size,  size);
points[6].set(-size,  size, -size);
points[7].set(-size,  size,  size);

NxSimpleTriangleMesh stm;
stm.numVertices = 8;
stm.numTriangles = 6*2;
stm.pointStrideBytes = sizeof(NxVec3);
stm.triangleStrideBytes = sizeof(NxU32)*3;

stm.points = points;
stm.triangles = triangles;
stm.flags |= NX_MF_FLIPNORMALS;
return gPhysicsSDK->createCCDSkeleton(stm);

}

4

Perhaps the force you apply is too high. Try to reduce it gradually to see what is the max force you can apply.

5

First of all what do you use for rendering the scene and actors? (The units in PhysX could be different than the renderer that you use). I use PhysX 3.2.1 - Irricht 1.7.3 no CCD enabled and I have no problems with collisions even when I have 1000 spheres joined together ;)

6

i am using Directx9 for rendering.
well i downloaded physx3.2.1 from PhysXInfo.com - MEGAGAME.AI
seems little bit different form ver 2.8.1. now just going through that sdk. after some time i will update my status.

thanks for the help :)