* Returns the parent of the given entity */

Computes the force->acceleration transformation matrix Such that: a = M*F */

computes the derivatives of a transformed inertial matrix, where originalInertia is the inertia around the center of mass of the transformed object lo

returned value is whether the last triangle checked was an edgePiece, in that case add it to the list

returns new trunkSize if removed, -1 if not removed