Abstract: A method and system for constructing a skeleton for use in animation models allows definition of a skeleton with non-articulated chain elements. These non-chain elements can be 3D objects, which can be rendered and visible in final images and animations, or null models which are not visible in final images or animations. All of the elements of the skeleton, including non-chain elements, are arranged into a skeleton hierarchy. The skeleton hierarchy can include articulated chain elements, articulated chain elements combined with non-chain elements, or solely non-chain elements. Relational information and/or mathematical relationships can be defined for the elements of the skeleton to define ranges of motion, elements which move with other elements and/or translation, rotation, scaling and/or animation of elements.

Abstract: A system and method for assigning the vertices of an envelope to one or more elements of a skeleton in an animation model. Bounding volumes are defined for skeleton elements and define effective volumes which are positioned relative to the skeleton elements to encompass one or more vertices of envelopes. The bounding volume geometry may be defined as desired and a desired assignment operation type is selected for the bounding volume. When automated assignment is performed, assignment of the vertices within the bounding volumes is performed in accordance with the selected assignment operation for each bounding volume and with a selected maximum number of elements to which each vertex may be assigned. Bounding volumes may be overlapped to provide versatile automated assignment and the bounding volumes and corresponding assignment operations are stored with the skeleton and therefore are independent of the envelopes employed.