又是PHYSX的问题，哪位指点一下！

pyhmail

我按照SDK文档中来创建一个流体：
//Set structure to pass particles, and receive them after every simulation step   
NxParticleData particles;
particles.numParticlesPtr = &gParticleBufferNum;   
particles.bufferPos = &gParticleBuffer[0].x;
particles.bufferPosByteStride = sizeof(NxVec3);
//Create a fluid descriptor
NxFluidDesc fluidDesc;
fluidDesc.kernelRadiusMultiplier = 2.3f;
fluidDesc.restParticlesPerMeter = 10.0f;
fluidDesc.stiffness = 200.0f;
fluidDesc.viscosity = 22.0f;
fluidDesc.restDensity = 1000.0f;
fluidDesc.damping = 0.0f;
fluidDesc.simulationMethod = NX_F_SPH;  
fluidDesc.initialParticleData = particles;   
fluidDesc.particlesWriteData = particles;
gFluid = gScene->createFluid(fluidDesc);
结果总是创建不成功，即gFluid == 0，什么原因呢？