def mass_information_fn(self, prim):
massInfo = UsdPhysics.RigidBodyAPI.MassInformation()
if prim.IsA(UsdGeom.Cube):
cubeLocalToWorldTransform = UsdGeom.Xformable(
prim).ComputeLocalToWorldTransform(Usd.TimeCode.Default())
extents = Gf.Transform(cubeLocalToWorldTransform).GetScale()
cube = UsdGeom.Cube(prim)
sizeAttr = cube.GetSizeAttr().Get()
sizeAttr = abs(sizeAttr)
extents = extents * sizeAttr
# cube volume
massInfo.volume = extents[0] * extents[1] * extents[2]
# cube inertia
inertia_diagonal = Gf.Vec3f(
1.0 / 12.0 *
(extents[1] * extents[1] + extents[2] * extents[2]), 1.0 /
12.0 * (extents[0] * extents[0] + extents[2] * extents[2]),
1.0 / 12.0 *
(extents[0] * extents[0] + extents[1] * extents[1]))
massInfo.inertia = Gf.Matrix3f(1.0)
massInfo.inertia.SetDiagonal(inertia_diagonal)
# CoM
massInfo.centerOfMass = Gf.Vec3f(0.0)
# local pose
if prim == self.rigidBodyPrim:
massInfo.localPos = Gf.Vec3f(0.0)
massInfo.localRot = Gf.Quatf(1.0)
else:
# massInfo.localPos, massInfo.localRot
lp, lr = self.get_collision_shape_local_transfrom(
cubeLocalToWorldTransform, self.rigidBodyWorldTransform)
massInfo.localPos = Gf.Vec3f(lp)
massInfo.localRot = Gf.Quatf(lr)
else:
print("UsdGeom type not supported.")
massInfo.volume = -1.0
return massInfo
def preTearDown(self, prim):
objects = self.getMObjects(prim)
nodePolyCube = self.objectFromString(objects[0])
pc = UsdGeom.Cube(prim)
self.writeEdits(pc, nodePolyCube)
return True
