An avar or animation variable (or hinge) is a variable controlling the position of part of an animated object, such as a character. The character "Woody" in Pixar's movie Toy Story uses 712 avars (with 212 in the face alone [1]). Successive sets of avars control all movement of the character from frame to frame. In development, they are used to define the junctions of a stick model (animation). Later, they are incorporated into a full wire frame model or a model built of polygons. Finally, surfaces are added, requiring a lengthy process of rendering to produce the final scene.
There are several ways of generating the avar values. Motion capture uses lights or markers on a real person acting out the part, tracked by a video camera. Toy Story uses no motion capture, manual control by a skilled animator can produce effects not easily carried out by a human actor.