2.87
fix issue with btMultiBody friction in combination with soft contacts (friction should not re-use normal contact cfm/erp) implement friction anchors, position friction correction, disabled by default. Use colObj->setCollisionFlag(flag | CF_HAS_FRICTION_ANCHOR); See test/RobotClientAPI/SlopeFrictionMain.cpp. In URDF or SDF, add <friction_anchor/> in <contact> section of <link> to enable. PhysicsServer: properly restore old activation state after releasing picked object btMultiBodyConstraintSolver: disable flip/flop of contact/friction constraint solving by default (it breaks some internal flaky unit tests)