Cartoon hair animation based on physical simulation

The hair movement in cel character animation is sometimes inconsistent. The representation of hair, therefore, is a specialized work in cel animation. It is difficult to achieve in computer graphics, since cel animation may not be consistent with all the hair’s attributes from all camera positions. In fact, what animators create by solving physics equations is not always what the animators desire even though it is physically correct. Also the motion of hair in cartoon animation carries meaning. Therefore, what the animators want exists only in their imagination, and all the hair forms (shape modeling and number of hairs) in the key frames from the animation sequence cannot be in complete agreement (Fig1). Quite convincing results, however, can be obtained from physically inconsistent frames. This is the most difficult part of expressing cartoon hair animation in computer graphics and is the reason why cartoon hair animation has been done by hand. It requires the instincts of an expert animator – and is very time consuming. In fact, the work of even a skilled animator is highly demanding. Yet there have been little researches[1] directed to the solutions to time-consuming problems such as the cel animation of hair motion.