AS 3 Biped Rig
This image shows the initial construction of the AS 3 Biped Rig, compared to the Character Studio equivalent. The AS 3 Biped is constructed in a similar manner, by dragging a rectangle on the screen. Rectangle dimensions are used to position bounding boxes for all limbs (either Bone Chains or Connectors). The bounding boxes are shown in Red.
Like the Character Studio Biped, the AS 3 Biped has a COM (Center Of Mass) that is selectable and can be translated and rotated. These transformations are passed along the entire limb hierarchy. Each Connector or Bone chain may be independently rotated. The FK architecture allows transformations to be passed along to multiple chains.
All Connectors and individual bones are drawn with externally specified Templates. The Template system allows bones to be used as a skin for a completely segmented character. Templates allow for uniform scaling along the bone’s radial dimension or non-uniform scaling to ensure the skin exactly fits a bounding box. In the future, Template control points could be interpolated with a piecewise Cubic Bezier spline (discussed in the Composite Bezier TechNote).
Currently, the rig is constructed with unconstrained FK. Next step is to add joint limits, although that will have to wait until I finish a quick gig for a client.