Abstract: An extensible character animation framework is provided that enables video game design teams to develop reusable animation controllers that are customizable for specific applications. According to embodiments, the animation framework enables animators to construct complex animations by creating hierarchies of animation controllers, and the complex animation is created by blending the animation outputs of each of the animation controllers in the hierarchy. The extensible animation framework also provides animators with the ability to customize various attributes of a character being animated and to view the changes to the animation in real-time in order to provide immediate feedback to the animators without requiring that the animators manually rebuild the animation data each time that the animators make a chance to the animation data.