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add mass scaling for reduced deformable model

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This commit is contained in:
jingyuc
2021-11-11 12:27:36 -05:00
parent 7fafbd7718
commit c2072b5538
5 changed files with 33 additions and 11 deletions
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4
data/reduced_cube/reduced_cube.urdf
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@@ -2,13 +2,13 @@
<robot name="reduced_cube">
<reduced_deformable name="reduced_cube">
<num_modes value="20"/>
<mass value="1"/>
<mass value="10"/>
<stiffness_scale value="100"/>
<collision_margin value="0.01"/>
<erp value= "0.2"/>
<cfm value= "0.2"/>
<friction value= "0.5"/>
<damping_coefficient value="0.0001"/>
<damping_coefficient value="0.0"/>
<visual filename="cube_mesh.vtk"/>
</reduced_deformable>
</robot>

15
examples/ReducedDeformableDemo/ReducedCollide.cpp
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@@ -30,7 +30,7 @@
// static btScalar E = 50;
// static btScalar nu = 0.3;
static btScalar damping_alpha = 0.0;
static btScalar damping_beta = 0.001;
static btScalar damping_beta = 0.0;
static btScalar COLLIDING_VELOCITY = 4;
static int start_mode = 6;
static int num_modes = 20;
@@ -75,11 +75,10 @@ public:
void Ctor_RbUpStack()
{
// float mass = 28;
float mass = 8;
float mass = 10;
// btCollisionShape* shape = new btBoxShape(btVector3(0.5, 0.5, 0.5));
btCollisionShape* shape = new btBoxShape(btVector3(1, 1, 1));
btCollisionShape* shape = new btBoxShape(btVector3(0.5, 0.5, 0.5));
// btCollisionShape* shape = new btBoxShape(btVector3(1, 1, 1));
btVector3 localInertia(0, 0, 0);
if (mass != 0.f)
shape->calculateLocalInertia(mass, localInertia);
@@ -102,7 +101,7 @@ public:
void rigidBar()
{
float mass = 8;
float mass = 10;
btCollisionShape* shape = new btBoxShape(btVector3(0.5, 0.25, 2));
btVector3 localInertia(0, 0, 0);
@@ -206,7 +205,7 @@ void ReducedCollide::initPhysics()
// create volumetric reduced deformable body
{
btReducedSoftBody* rsb = btReducedSoftBodyHelpers::createReducedBeam(getDeformableDynamicsWorld()->getWorldInfo(), start_mode, num_modes);
btReducedSoftBody* rsb = btReducedSoftBodyHelpers::createReducedCube(getDeformableDynamicsWorld()->getWorldInfo(), start_mode, num_modes);
getDeformableDynamicsWorld()->addSoftBody(rsb);
rsb->getCollisionShape()->setMargin(0.1);
@@ -221,6 +220,8 @@ void ReducedCollide::initPhysics()
rsb->setStiffnessScale(100);
rsb->setDamping(damping_alpha, damping_beta);
rsb->setTotalMass(15);
rsb->m_cfg.kKHR = 1; // collision hardness with kinematic objects
rsb->m_cfg.kCHR = 1; // collision hardness with rigid body
rsb->m_cfg.kDF = 0;

2
examples/SharedMemory/PhysicsServerCommandProcessor.cpp
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@@ -9525,6 +9525,8 @@ bool PhysicsServerCommandProcessor::processReducedDeformable(const UrdfReducedDe
rsb->setStiffnessScale(reduced_deformable.m_stiffnessScale);
rsb->setDamping(0, reduced_deformable.m_damping); // damping alpha is set to 0 by default
btReducedSoftBodyHelpers::readReducedDeformableInfoFromFiles(rsb, pathPrefix);
// set total mass
rsb->setTotalMass(reduced_deformable.m_mass);
}
#endif
}

2
examples/pybullet/examples/reduced_deformable_cube.py
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@@ -13,7 +13,7 @@ p.setGravity(0, 0, -10)
tex = p.loadTexture("uvmap.png")
planeId = p.loadURDF("plane.urdf", [0,0,-2])
p.startStateLogging(p.STATE_LOGGING_VIDEO_MP4, "reduced_cube.mp4")
# p.startStateLogging(p.STATE_LOGGING_VIDEO_MP4, "reduced_cube.mp4")
cube = p.loadURDF("reduced_cube/reduced_cube.urdf", [1,1,1])
p.changeVisualShape(cube, -1, rgbaColor=[1,1,1,1], textureUniqueId=tex, flags=0)
p.setPhysicsEngineParameter(sparseSdfVoxelSize=0.25)

21
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBody.cpp
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@@ -463,7 +463,26 @@ void btReducedSoftBody::scale(const btVector3& scl)
void btReducedSoftBody::setTotalMass(btScalar mass, bool fromfaces)
{
//
btScalar scale_ratio = mass / m_mass;
// update nodal mass
for (int i = 0; i < m_nFull; ++i)
{
m_nodalMass[i] *= scale_ratio;
}
m_mass = mass;
m_inverseMass = mass > 0 ? 1.0 / mass : 0;
// update inertia tensors
updateLocalInertiaTensorFromNodes();
btMatrix3x3 id;
id.setIdentity();
updateInitialInertiaTensor(id); // there is no rotation, but the local inertia tensor has changed
updateInertiaTensor();
m_interpolateInvInertiaTensorWorld = m_invInertiaTensorWorld;
internalInitialization();
}
void btReducedSoftBody::updateRestNodalPositions()