ABSTRACT
Hair is an important aspect of creating believable facial models. Realistic synthetic human images need realistic hair models and realistic hair motion. Such representations of human hair present challenges to all aspects of computer graphics, including shape modeling, animation, and rendering.
Hair is composed of fibrous protein structures originating in follicle structures integrated into the skin, as shown in Figure 3.28. Hair follicles are tubular epidermal structures. The wall of the follicle forms an inner and outer sheath for the hair. The inner sheath grows up with the hair and has two layers: the outer Henle layer and the inner Huxley layer. It also has a thin cuticle of cells that interlock with the scales of the hair cuticle. From the base of the follicle up to the skin, the hair has three regions: the rounded bulb containing the papilla, then a region where the hair is enclosed by the inner sheath, and finally the neck of the follicle [Ryder 73].
