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use deformable contact detection for the reduced deformable model

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This commit is contained in:
jingyuc 2021-08-10 16:31:53 -04:00
parent 3425c01acc
commit 6355b06a8b
8 changed files with 96 additions and 26 deletions
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2
examples/ReducedDeformableDemo/BasicTest.cpp
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@ -48,7 +48,7 @@ class BasicTest : public CommonDeformableBodyBase
// rsb->m_nodes[i].m_x[k] += rsb->m_modes[mode_n][3 * i + k] * scale;
rsb->m_reducedDofs[mode_n] = scale;
rsb->mapToFullDofs(rsb->getWorldTransform());
rsb->mapToFullPosition(rsb->getWorldTransform());
std::cout << "-----------\n";
std::cout << rsb->m_nodes[0].m_x[0] << '\t' << rsb->m_nodes[0].m_x[1] << '\t' << rsb->m_nodes[0].m_x[2] << '\n';
std::cout << "-----------\n";

30
examples/ReducedDeformableDemo/FreeFall.cpp
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@ -94,20 +94,26 @@ public:
// btSoftBodyHelpers::Draw(rsb, deformableWorld->getDebugDrawer(), flag);
btSoftBodyHelpers::Draw(rsb, deformableWorld->getDebugDrawer(), deformableWorld->getDrawFlags());
btVector3 origin = rsb->getRigidTransform().getOrigin();
btVector3 line_x = rsb->getRigidTransform().getBasis() * 2 * btVector3(1, 0, 0) + origin;
btVector3 line_y = rsb->getRigidTransform().getBasis() * 2 * btVector3(0, 1, 0) + origin;
btVector3 line_z = rsb->getRigidTransform().getBasis() * 2 * btVector3(0, 0, 1) + origin;
// btVector3 origin = rsb->getRigidTransform().getOrigin();
// btVector3 line_x = rsb->getRigidTransform().getBasis() * 2 * btVector3(1, 0, 0) + origin;
// btVector3 line_y = rsb->getRigidTransform().getBasis() * 2 * btVector3(0, 1, 0) + origin;
// btVector3 line_z = rsb->getRigidTransform().getBasis() * 2 * btVector3(0, 0, 1) + origin;
deformableWorld->getDebugDrawer()->drawLine(origin, line_x, btVector3(1, 0, 0));
deformableWorld->getDebugDrawer()->drawLine(origin, line_y, btVector3(0, 1, 0));
deformableWorld->getDebugDrawer()->drawLine(origin, line_z, btVector3(0, 0, 1));
// deformableWorld->getDebugDrawer()->drawLine(origin, line_x, btVector3(1, 0, 0));
// deformableWorld->getDebugDrawer()->drawLine(origin, line_y, btVector3(0, 1, 0));
// deformableWorld->getDebugDrawer()->drawLine(origin, line_z, btVector3(0, 0, 1));
for (int p = 0; p < rsb->m_fixedNodes.size(); ++p)
{
deformableWorld->getDebugDrawer()->drawSphere(rsb->m_nodes[rsb->m_fixedNodes[p]].m_x, 0.2, btVector3(1, 0, 0));
// std::cout << rsb->m_nodes[rsb->m_fixedNodes[p]].m_x[0] << "\t" << rsb->m_nodes[rsb->m_fixedNodes[p]].m_x[1] << "\t" << rsb->m_nodes[rsb->m_fixedNodes[p]].m_x[2] << "\n";
}
for (int p = 0; p < rsb->m_contactNodesList.size(); ++p)
{
deformableWorld->getDebugDrawer()->drawSphere(rsb->m_nodes[rsb->m_contactNodesList[p]].m_x, 0.2, btVector3(0, 1, 0));
// std::cout << rsb->m_nodes[rsb->m_fixedNodes[p]].m_x[0] << "\t" << rsb->m_nodes[rsb->m_fixedNodes[p]].m_x[1] << "\t" << rsb->m_nodes[rsb->m_fixedNodes[p]].m_x[2] << "\n";
}
deformableWorld->getDebugDrawer()->drawSphere(btVector3(0, 0, 0), 0.1, btVector3(1, 1, 1));
deformableWorld->getDebugDrawer()->drawSphere(btVector3(0, 5, 0), 0.1, btVector3(1, 1, 1));
deformableWorld->getDebugDrawer()->drawSphere(btVector3(0, 10, 0), 0.1, btVector3(1, 1, 1));
@ -129,7 +135,7 @@ void FreeFall::initPhysics()
m_broadphase = new btDbvtBroadphase();
btReducedSoftBodySolver* reducedSoftBodySolver = new btReducedSoftBodySolver();
reducedSoftBodySolver->setDamping(damping_alpha, damping_beta);
btVector3 gravity = btVector3(0, -10, 0);
btVector3 gravity = btVector3(0, 0, 0);
reducedSoftBodySolver->setGravity(gravity);
btDeformableMultiBodyConstraintSolver* sol = new btDeformableMultiBodyConstraintSolver();
@ -152,7 +158,7 @@ void FreeFall::initPhysics()
getDeformableDynamicsWorld()->addSoftBody(rsb);
rsb->getCollisionShape()->setMargin(0.1);
// rsb->scale(btVector3(1, 1, 1));
rsb->translate(btVector3(0, 5, 0)); //TODO: add back translate and scale
rsb->translate(btVector3(0, 0.1, 0)); //TODO: add back translate and scale
// rsb->setTotalMass(0.5);
rsb->setStiffnessScale(0.5);
@ -168,7 +174,7 @@ void FreeFall::initPhysics()
btSoftBodyHelpers::generateBoundaryFaces(rsb);
// rsb->setVelocity(btVector3(0, -COLLIDING_VELOCITY, 0));
// rsb->setRigidVelocity(btVector3(0, 1, 0));
rsb->setRigidVelocity(btVector3(0, 0, 1));
// rsb->setRigidAngularVelocity(btVector3(1, 0, 0));
// btDeformableGravityForce* gravity_force = new btDeformableGravityForce(gravity);
@ -177,12 +183,12 @@ void FreeFall::initPhysics()
}
// create a static rigid box as the ground
{
btBoxShape* groundShape = createBoxShape(btVector3(btScalar(50.), btScalar(50.), btScalar(50.)));
btBoxShape* groundShape = createBoxShape(btVector3(btScalar(5.), btScalar(5.), btScalar(0.5)));
m_collisionShapes.push_back(groundShape);
btTransform groundTransform;
groundTransform.setIdentity();
groundTransform.setOrigin(btVector3(0, -50, 0));
groundTransform.setOrigin(btVector3(0, 0, 5));
{
btScalar mass(0.);
createRigidBody(mass, groundTransform, groundShape, btVector4(0,0,0,0));

3
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBody.cpp
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@ -122,6 +122,7 @@ void btReducedSoftBody::setMassScale(const btScalar rho)
void btReducedSoftBody::setFixedNodes(const int n_node)
{
m_fixedNodes.push_back(n_node);
m_nodes[n_node].m_im = 0; // set inverse mass to be zero for the constraint solver.
}
void btReducedSoftBody::internalInitialization()
@ -235,7 +236,7 @@ void btReducedSoftBody::updateReducedDofs(btScalar solverdt)
}
}
void btReducedSoftBody::mapToFullDofs(const btTransform& ref_trans)
void btReducedSoftBody::mapToFullPosition(const btTransform& ref_trans)
{
btVector3 origin = ref_trans.getOrigin();
btMatrix3x3 rotation = ref_trans.getBasis();

4
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBody.h
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@ -76,6 +76,8 @@ class btReducedSoftBody : public btSoftBody
tDenseArray m_nodalMass; // Mass on each node
btAlignedObjectArray<int> m_fixedNodes; // index of the fixed nodes
btAlignedObjectArray<int> m_contactNodesList;
//
// Api
//
@ -133,7 +135,7 @@ class btReducedSoftBody : public btSoftBody
void updateReducedVelocity(btScalar solverdt);
// map to full degree of freedoms
void mapToFullDofs(const btTransform& ref_trans);
void mapToFullPosition(const btTransform& ref_trans);
// compute full space velocity from the reduced velocity
void mapToFullVelocity(const btTransform& ref_trans);

67
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBodySolver.cpp
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@ -34,6 +34,23 @@ void btReducedSoftBodySolver::predictReduceDeformableMotion(btScalar solverdt)
{
btReducedSoftBody* rsb = static_cast<btReducedSoftBody*>(m_softBodies[i]);
// clear contacts variables
rsb->m_nodeRigidContacts.resize(0);
rsb->m_faceRigidContacts.resize(0);
rsb->m_faceNodeContacts.resize(0);
// calculate inverse mass matrix for all nodes
if (rsb->isActive())
{
for (int j = 0; j < rsb->m_nodes.size(); ++j)
{
if (rsb->m_nodes[j].m_im > 0)
{
rsb->m_nodes[j].m_effectiveMass_inv = rsb->m_nodes[j].m_effectiveMass.inverse();
}
}
}
// apply damping
rsb->applyDamping(solverdt);
@ -53,6 +70,17 @@ void btReducedSoftBodySolver::predictReduceDeformableMotion(btScalar solverdt)
// predict full space velocity (needed for constraints)
rsb->mapToFullVelocity(rsb->getInterpolationWorldTransform());
// update full space nodal position
rsb->mapToFullPosition(rsb->getInterpolationWorldTransform());
// update bounding box
rsb->updateBounds();
// std::cout << "bounds\n";
// std::cout << rsb->m_bounds[0][0] << '\t' << rsb->m_bounds[0][1] << '\t' << rsb->m_bounds[0][2] << '\n';
// std::cout << rsb->m_bounds[1][0] << '\t' << rsb->m_bounds[1][1] << '\t' << rsb->m_bounds[1][2] << '\n';
// apply fixed constraints
// rsb->applyFixedContraints(solverdt);
@ -96,7 +124,7 @@ void btReducedSoftBodySolver::applyTransforms(btScalar timeStep)
rsb->proceedToTransform(timeStep, true);
// update mesh nodal positions for the next time step
rsb->mapToFullDofs(rsb->getRigidTransform());
rsb->mapToFullPosition(rsb->getRigidTransform());
// end of time step clean up and update
rsb->endOfTimeStepZeroing();
@ -104,7 +132,42 @@ void btReducedSoftBodySolver::applyTransforms(btScalar timeStep)
m_simTime += timeStep;
}
void btReducedSoftBodySolver::solveConstraints(btScalar timeStep)
void btReducedSoftBodySolver::setConstraints(const btContactSolverInfo& infoGlobal)
{
for (int i = 0; i < m_softBodies.size(); ++i)
{
btReducedSoftBody* rsb = static_cast<btReducedSoftBody*>(m_softBodies[i]);
// set fixed constraints
for (int j = 0; j < rsb->m_nodes.size(); ++j)
{
// if (rsb->m_nodes[j].m_im == 0)
// {
// btDeformableStaticConstraint static_constraint(&rsb->m_nodes[j], infoGlobal);
// m_staticConstraints[i].push_back(static_constraint);
// }
}
// set Deformable Node vs. Rigid constraint
rsb->m_contactNodesList.clear();
for (int j = 0; j < rsb->m_nodeRigidContacts.size(); ++j)
{
rsb->m_contactNodesList.push_back(rsb->m_nodeRigidContacts[j].m_node->index);
// const btSoftBody::DeformableNodeRigidContact& contact = rsb->m_nodeRigidContacts[j];
// // skip fixed points
// if (contact.m_node->m_im == 0)
// {
// continue;
// }
// btDeformableNodeRigidContactConstraint constraint(contact, infoGlobal);
// m_nodeRigidConstraints[i].push_back(constraint);
}
std::cout << "#contact nodes: " << rsb->m_contactNodesList.size() << "\n";
}
}
void btReducedSoftBodySolver::solveDeformableConstraints(btScalar timeStep)
{
for (int iter = 0; iter < 100; ++iter) // TODO: add a fllag for this.
{

7
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBodySolver.h
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@ -36,7 +36,11 @@ class btReducedSoftBodySolver : public btDeformableBodySolver
virtual void applyTransforms(btScalar timeStep);
virtual void solveConstraints(btScalar timeStep);
// set up contact constraints
virtual void setConstraints(const btContactSolverInfo& infoGlobal);
// solve all constraints (fixed and contact)
virtual void solveDeformableConstraints(btScalar solverdt);
// virtual void setProjection() {}
@ -44,7 +48,6 @@ class btReducedSoftBodySolver : public btDeformableBodySolver
// virtual void setupDeformableSolve(bool implicit);
// virtual void solveDeformableConstraints(btScalar solverdt);
};
#endif // BT_REDUCED_SOFT_BODY_DYNAMICS_WORLD_H

6
src/BulletSoftBody/btDeformableBodySolver.h
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@ -72,7 +72,7 @@ public:
void reinitialize(const btAlignedObjectArray<btSoftBody*>& softBodies, btScalar dt);
// set up contact constraints
void setConstraints(const btContactSolverInfo& infoGlobal);
virtual void setConstraints(const btContactSolverInfo& infoGlobal);
// add in elastic forces and gravity to obtain v_{n+1}^* and calls predictDeformableMotion
virtual void predictMotion(btScalar solverdt);
@ -199,11 +199,9 @@ public:
m_objective->m_projection.setLagrangeMultiplier();
}
virtual void solveConstraints(btScalar timeStep) {}
// unused functions
virtual void optimize(btAlignedObjectArray<btSoftBody*>& softBodies, bool forceUpdate = false) {}
// virtual void solveConstraints(btScalar dt) {}
virtual void solveConstraints(btScalar dt) {}
virtual bool checkInitialized() { return true; }
virtual void copyBackToSoftBodies(bool bMove = true) {}
};

3
src/BulletSoftBody/btDeformableMultiBodyDynamicsWorld.cpp
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@ -326,9 +326,6 @@ void btDeformableMultiBodyDynamicsWorld::solveConstraints(btScalar timeStep)
// At this point, dv should be golden for nodes in contact
// proceed to solve deformable momentum equation
m_deformableBodySolver->solveDeformableConstraints(timeStep);
// TODO: need better design
m_deformableBodySolver->solveConstraints(timeStep);
}
void btDeformableMultiBodyDynamicsWorld::setupConstraints()