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Merge pull request #2709 from xhan0619/master

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Tune deformable collision parameters for more stable deformable vs. d…
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erwincoumans 2020-04-01 19:14:51 -07:00 committed by GitHub
commit c661179554
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4 changed files with 18 additions and 17 deletions
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23
examples/DeformableDemo/DeformableSelfCollision.cpp
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@ -50,8 +50,8 @@ public:
void stepSimulation(float deltaTime)
{
float internalTimeStep = 1. / 480.f;
m_dynamicsWorld->stepSimulation(deltaTime, 8, internalTimeStep);
float internalTimeStep = 1. / 240.f;
m_dynamicsWorld->stepSimulation(deltaTime, 4, internalTimeStep);
}
void addCloth(btVector3 origin);
@ -114,12 +114,13 @@ void DeformableSelfCollision::initPhysics()
btDefaultMotionState* myMotionState = new btDefaultMotionState(groundTransform);
btRigidBody::btRigidBodyConstructionInfo rbInfo(mass, myMotionState, groundShape, localInertia);
btRigidBody* body = new btRigidBody(rbInfo);
body->setFriction(40);
body->setFriction(4);
//add the ground to the dynamics world
m_dynamicsWorld->addRigidBody(body);
}
addCloth(btVector3(0, -0.4, 0));
addCloth(btVector3(0, -0.1, 0));
addCloth(btVector3(0, 1, 0));
getDeformableDynamicsWorld()->setImplicit(false);
getDeformableDynamicsWorld()->setLineSearch(false);
m_guiHelper->autogenerateGraphicsObjects(m_dynamicsWorld);
@ -134,29 +135,29 @@ void DeformableSelfCollision::addCloth(btVector3 origin)
btVector3(+s, h, -2*s),
btVector3(-s, h, +2*s),
btVector3(+s, h, +2*s),
20,40,
15,30,
// 4,4,
0, true, 0.0);
psb->getCollisionShape()->setMargin(0.0075);
psb->generateBendingConstraints(3);
psb->getCollisionShape()->setMargin(0.02);
psb->generateBendingConstraints(2);
psb->setTotalMass(.5);
psb->m_cfg.kKHR = 1; // collision hardness with kinematic objects
psb->m_cfg.kCHR = 1; // collision hardness with rigid body
psb->m_cfg.kDF = 0.1;
psb->rotate(btQuaternion(0, SIMD_PI / 2, 0));
psb->rotate(btQuaternion(0, SIMD_PI / 4, 0));
btTransform clothTransform;
clothTransform.setIdentity();
clothTransform.setOrigin(btVector3(0,0.2,0));
clothTransform.setOrigin(btVector3(0,0.2,0)+origin);
psb->transform(clothTransform);
psb->m_cfg.collisions = btSoftBody::fCollision::SDF_RD;
psb->m_cfg.collisions |= btSoftBody::fCollision::VF_DD;
getDeformableDynamicsWorld()->addSoftBody(psb);
psb->setSelfCollision(true);
btDeformableMassSpringForce* mass_spring = new btDeformableMassSpringForce(1.5,0.1, true);
psb->setSpringStiffness(1);
btDeformableMassSpringForce* mass_spring = new btDeformableMassSpringForce(2,0.1, true);
psb->setSpringStiffness(2);
getDeformableDynamicsWorld()->addForce(psb, mass_spring);
m_forces.push_back(mass_spring);
btVector3 gravity = btVector3(0, -9.8, 0);

2
src/BulletSoftBody/btDeformableMultiBodyDynamicsWorld.cpp
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@ -63,7 +63,7 @@ m_deformableBodySolver(deformableBodySolver), m_solverCallback(0)
m_implicit = false;
m_lineSearch = false;
m_selfCollision = true;
m_ccdIterations = 3;
m_ccdIterations = 5;
m_solverDeformableBodyIslandCallback = new DeformableBodyInplaceSolverIslandCallback(constraintSolver, dispatcher);
}

4
src/BulletSoftBody/btSoftBody.cpp
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@ -4139,7 +4139,7 @@ void btSoftBody::defaultCollisionHandler(btSoftBody* psb)
if (psb->useSelfCollision())
{
btSoftColliders::CollideFF_DD docollide;
docollide.mrg = getCollisionShape()->getMargin()*2.0;
docollide.mrg = getCollisionShape()->getMargin();
docollide.psb[0] = this;
docollide.psb[1] = psb;
if (this->m_tetras.size() > 0)
@ -4196,7 +4196,7 @@ void btSoftBody::geometricCollisionHandler(btSoftBody* psb)
if (psb->useSelfCollision())
{
btSoftColliders::CollideCCD docollide;
docollide.mrg = 1e-6;
docollide.mrg = SAFE_EPSILON;
docollide.psb[0] = this;
docollide.psb[1] = psb;
docollide.dt = psb->m_sst.sdt;

6
src/BulletSoftBody/btSoftBody.h
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@ -1173,7 +1173,7 @@ public:
static psolver_t getSolver(ePSolver::_ solver);
static vsolver_t getSolver(eVSolver::_ solver);
void geometricCollisionHandler(btSoftBody* psb);
#define SAFE_EPSILON SIMD_EPSILON*10.0
#define SAFE_EPSILON SIMD_EPSILON*100.0
void updateNode(btDbvtNode* node, bool use_velocity, bool margin)
{
if (node->isleaf())
@ -1307,7 +1307,7 @@ public:
bool face_constrained = false, node_constrained = node->m_constrained;
for (int i = 0; i < 3; ++i)
face_constrained |= face->m_n[i]->m_constrained;
btScalar I_tilde = 2.0*I /(1.0+w.length2());
btScalar I_tilde = .5 *I /(1.0+w.length2());
// double the impulse if node or face is constrained.
if (face_constrained || node_constrained)
@ -1331,7 +1331,7 @@ public:
btScalar vt_new = btMax(btScalar(1) - mu * delta_vn / (vt_norm + SIMD_EPSILON), btScalar(0))*vt_norm;
I = 0.5 * mass * (vt_norm-vt_new);
vt.safeNormalize();
I_tilde = 2.0*I /(1.0+w.length2());
I_tilde = .5 *I /(1.0+w.length2());
// double the impulse if node or face is constrained.
if (face_constrained || node_constrained)
I_tilde *= 2.0;