private Momentum computeMomentum(RigidBody elevator, ReferenceFrame frame) { elevator.updateFramesRecursively(); TwistCalculator twistCalculator = new TwistCalculator(world, elevator); twistCalculator.compute(); MomentumCalculator momentumCalculator = new MomentumCalculator(twistCalculator); Momentum momentum = new Momentum(frame); momentumCalculator.computeAndPack(momentum); return momentum; }