Skeletal Animation

Overview

This chapter discusses concepts such as vertex blending, vertex skinning and keyframing that are fundamental to the animation of articulated character models. Vertex blending is the process of constructing blending surfaces between two different parts that move relative to each other, in order to create the appearance of a single deformable object. Vertex blending is useful in the animation of character models constructed by joining together several individual components.

Mesh models of animatable characters are often subdivided into groups of vertices that represent moveable body parts. A skeleton is an abstract representation of this form of partitioning of a mesh. Skeletal animation refers to the process of computing the transformations of each segment in the skeleton using joint angles, and mapping them on to mesh vertices. The chapter discusses various stages in skeletal animation, describes the transformations applied to a mesh, and also outlines a scene graph based implementation.