values defining the morph targets coefficients or rotation and translation values of the bones in models with a bone based rig. Often to speed up the keyframe animation process a control rig is used by the animation. The control rig represents a higher level of abstraction that can act on multiple morph targets coefficients or bones at the same time. For example, a "smile" control can act simultaneously on the mouth shape curving up and the eyes squinting. Applying facial animation to a character The main techniques used to apply facial animation to a character are: 1.) morph targets animation, 2.) bone driven animation, 3.) texture-based animation (2D or 3D), and 4.) physiological models. Morph targets (also called "blendshapes") based systems offer a fast playback as well as a high degree of fidelity of expressions. The technique involves modeling portions of the face mesh to approximate expressions and visemes and then blending the different sub meshes, known as morph targets or blendshapes. Perhaps the most accomplished character using this technique was Gollum, from The Lord of the Rings. Drawbacks of this technique are that they involve intensive manual labor and are specific to each character. Recently, new concepts in 3D modeling have started to emerge. Recently, a new technology departing from the traditional techniques starts to emerge, such as Curve Controlled Modeling that emphasizes the modeling of the movement of a 3D object instead of the traditional modeling of the static shape. Bone driven animation is very broadly used in games. The bones setup can vary between few bones to close to a hundred to allow all subtle facial expressions. The main advantages of bone driven animation is that the same animation can be used for different characters as long as the morphology of their faces is similar, and secondly they do not require loading in memory all the Morph targets data. Bone driven animation is most widely supported by 3D game engines. Bone driven animation can be used for both 2D and 3D animation. For example, it is possible to rig and animate using bones a 2D character using Adobe Flash. Texture-based animation uses pixel color to create the animation on the character face. 2D facial animation is commonly based upon the transformation of images, including both images from still photography and sequences of video. Image morphing is a technique which allows in-between transitional images to be generated between