The Biped controller, referred to as "<biped_ctrl>" in this documentation, is called the Biped Vertical_Horizontal_Turn(Body):Matrix3 Controller. This is sometimes also called the body controller because it is equivalent to the Biped’s.transform.controller.
The Biped footsteps have a controller. It is referred to as "<footsteps_ctrl>" in this documentation. See Biped Footsteps for details regarding the FootSteps:Matrix3 Controller.
Individual Biped body part objects and the Vertical, Horizontal, and Turning tracks of the Biped Vertical Horizontal Turn(Body):Matrix3_Controller use the Biped Slave Controller. This type of controller is attached to the transform track.
In addition, a new Biped SubAnim Controller has been introduced in character studio 4.
Biped Vertical_Horizontal_Turn(Body):Matrix3 Controller
Biped Slave Controller
Biped SubAnim Controller
Biped MAXScript Extensions