When you solve a dynamics solution in the Dynamics utility, the Dynamics controllers are assigned as the position and rotation controllers of all objects not flagged as unyielding. These controllers are similar to List controllers in that they contain multiple sub-controllers. The first sub-controller is a Bezier controller of the appropriate type that contains the keys generated while solving the dynamics solution. This controller can be accessed as the Dynamic_position_controller or Dynamic_rotation_controller property of the dynamics controller. The second sub-controller is the original position or rotation controller assigned to the object, and can be accessed as the old_position or old_position property.