The effect: Pieces break apart according to a bunch of paths, on an object that is moving/deforming. In parts, we have to: (1) Fracture the sphere according to some paths. (2) Have the pieces start out as part of the keyframed animation e.g. as part of the spinning globe, and then switch over to being simulated by the RBD Solver when some “trigger” happens. @active and @deforming We learned previously, the RBD Solver looks for the attribute i@active on the pieces to determine whether they are “reactive” in a sim.

Transform Pieces moves stuff around with points. [Above] We use one point to move one box. Transform Pieces takes three inputs: [ A ] Points to transform. [ B ] Points that will move the A-points. [ C ] Rest positions of B before the move. Houdini binds the A-points to the B-points by matching a user-specified attribute that exists on both. In our tree, Assemble packs the box – reducing it to a single A-point – which is then driven by the single B-point.