void create(NxScene& scene, const NxVec3& pos, float rad, NxActor* holder)
		{
			NxActorDesc actorDesc;
			NxBodyDesc bodyDesc;

			bodyDesc.solverIterationCount = 20;

			// steer axis
			bodyDesc.mass = 50;
			bodyDesc.massSpaceInertia = NxVec3(1,1,1);
			actorDesc.body = &bodyDesc;
			actorDesc.shapes.clear();

			actorDesc.globalPose.t = pos;
			steerAxis = scene.createActor(actorDesc);
			wheel.create(scene, pos, rad, steerAxis);

			// revolute joint connecting steerAxis with the holder
			NxRevoluteJointDesc revJointDesc;
			revJointDesc.projectionMode = NX_JPM_POINT_MINDIST;
			revJointDesc.actor[0] = steerAxis;
			revJointDesc.actor[1] = holder;
			revJointDesc.setGlobalAnchor(pos);
			revJointDesc.setGlobalAxis(NxVec3(0,1,0));
			steerJoint = (NxRevoluteJoint*)scene.createJoint(revJointDesc);

			// disable collision detection 
			scene.setActorPairFlags(*wheel.wheel, *holder, NX_IGNORE_PAIR);
		}
		void create(NxScene& scene, const NxVec3& pos, float rad, NxActor* holder)
		{
			NxActorDesc actorDesc;
			NxBodyDesc bodyDesc;
			NxSphereShapeDesc sphereDesc;
			
			bodyDesc.solverIterationCount = 20;

			// wheel
			sphereDesc.radius = rad;
			sphereDesc.materialIndex = wheelMaterialIndex;
			actorDesc.shapes.pushBack(&sphereDesc);
			bodyDesc.mass = 400;
			actorDesc.body = &bodyDesc;
			actorDesc.globalPose.t = pos;
			wheel = scene.createActor(actorDesc);

			// roll axis
			bodyDesc.mass = 50;
			bodyDesc.massSpaceInertia = NxVec3(1,1,1);
			actorDesc.body = &bodyDesc;
			actorDesc.shapes.clear();
			actorDesc.globalPose.t  = pos;
			rollAxis = scene.createActor(actorDesc);
			
			// revolute joint connecting wheel with rollAxis
			NxRevoluteJointDesc revJointDesc;
			revJointDesc.projectionMode = NX_JPM_POINT_MINDIST;
			revJointDesc.actor[0] = wheel;
			revJointDesc.actor[1] = rollAxis;
			revJointDesc.setGlobalAnchor(pos);
			revJointDesc.setGlobalAxis(NxVec3(0,0,1));
			rollJoint = (NxRevoluteJoint*)scene.createJoint(revJointDesc);

			// prismatic joint connecting rollAxis with holder
			NxPrismaticJointDesc prisJointDesc;
			prisJointDesc.actor[0] = rollAxis;
			prisJointDesc.actor[1] = holder;
			prisJointDesc.setGlobalAnchor(pos);
			prisJointDesc.setGlobalAxis(NxVec3(0,1,0));
			scene.createJoint(prisJointDesc);

			// add springs and dampers to the suspension (i.e. the related actors)
			float springLength = 0.1f;
			NxSpringAndDamperEffector * springNdamp = scene.createSpringAndDamperEffector(NxSpringAndDamperEffectorDesc());

			springNdamp->setBodies(rollAxis, pos, holder, pos + NxVec3(0,springLength,0));
			springNdamp->setLinearSpring(0, springLength, 2*springLength, 100000, 100000);
			springNdamp->setLinearDamper(-1, 1, 1e5, 1e5);

			// disable collision detection 
			scene.setActorPairFlags(*wheel, *holder, NX_IGNORE_PAIR);
		}