Real-Time Physics Simulation Forum

Re: breakable constraints

2009-11-04T20:32:30+00:00

OK I have a nearly working system but I need to access the btDiscreteDynamicsWorld from btRigidBody to perform the removeConstraint function.

Code:

void btRigidBody::checkToBreakConstraints(){for (int i = 0; i < m_constraintRefs.size(); ++i){btTypedConstraint* constraint = m_constraintRefs[i];if(constraint->getBreakable()){btScalar imp1 = constraint->getAppliedImpulse();btScalar imp = imp1 * imp1;if(imp > constraint->getBreakThreshold())        }}}

As you can tell I added a flag and a float to use for detecting if the joint is breakable and what the break threshold would be. Can someone tell me how to access the world so I can call the function?

Statistics: Posted by RJNelson68 — Wed Nov 04, 2009 8:32 pm

Re: breakable constraints

2009-11-04T05:19:31+00:00

I realize this is an old post, but where could you detect the constraint's id? I am just looking for a place that this could be utilized becasue as far as I can tell the forces applied to the joints are not exposed to use something like this.

Statistics: Posted by RJNelson68 — Wed Nov 04, 2009 5:19 am

breakable constraints

2006-07-03T17:05:48+00:00

To trigger breaking chains, collapsing bridges etc. there is a new getAppliedImpulse to measure 'stress' on the constraints. A bridge can be build using 'hinge' constraint, or a bunch of point-to-point constraints.

The stress/appliedImpulse can be read out in the very latest RC3 preview43 build, see the included breaking_chain.blend.

Win32:
http://www.continuousphysics.com/ftp/pu ... indows.zip

Linux:
http://www.continuousphysics.com/ftp/pu ... view43.tgz

Code:

#shows breaking constraints dependent on constraint 'appliedImpulse'import PhysicsConstraintsimport GameLogicob = GameLogic.getCurrentController().getOwner()#ob.id points to the constraint idimp1 = PhysicsConstraints.getAppliedImpulse(ob.id)imp = imp1*imp1print impbreakingTreshold = 0.82if imp>breakingTreshold:    PhysicsConstraints.removeConstraint(ob.id)

Erwin

Statistics: Posted by Erwin Coumans — Mon Jul 03, 2006 5:05 pm