...
We have talked a lot about prefractured objects in the previous chapters, and this type is indeed one of the main fields of application for MultiJoints. MultiJoints can be seen as dynamic connections for connecting objects. Let's take a look at a scene with a fractured, rigid body node. Shortly after the beginning of the simulation, the pieces start to break apart, because they are treated as individual nodes without any connection. In order to prevent this, the fragments have to be reconnected and this can be done with MultiJoints. Another, very common, way to use this system is the simulation of different hinges and limbs.
[ Image: Fractured wall with MJ ]
MultiJoints act on forces. Let's stay with the fragmented object: it takes a certain amount of force to prevent the fragments from falling apart. If this force is higher, than the counteracting force which tries to attract the fragments (gravity for example) then the pieces will stick together. If an external event adds another force then some of the connections will break. Typical sources for external forces are daemons, moving fluids, or other interacting bodies.
...