12/01/1990 09:00 AM
Computer Science
One of the difficult problems in computer character animation has been creating a skin model which deforms naturally over joints. A method for solving this problem is described, which includes such desirable characteristics as the formation of creases on the inside of joints and muscle bulging during flexing. In this model the skin is represented using a mesh of bicubic surface patches, with the control points acting as sample points in a constraint balancing equation. Two main constraints are used: the skin is described as a flexible surface that resists stretching, and bones, fat, and muscle are represented by localized fields pushing out on the skin. The final shape of the figure is a compromise between the skin\'s surface area constraints and the arrangement of underlying tissue. Modeling with bicubic patches allows the granularity of the constraint computations to be much more coarse than if a polygonal model were used, and provides for well-defined and stable surface texture coordinates. In addition, this method is capable of incorporating tissue- bouncing due to rigid body motion. Notes: M.S. Thesis
