| Modeling and rendering human hair is a very challenging problem in computer graphics. The difficulty comes mainly from the amount of hairs to be modeled, the fine details of the individual hairs, and the complex illumination properties among different hair strands. In this thesis, a new hair model is introduced. The new model allows the design and styling of hairs to be efficiently performed at an abstract cluster level. The key idea of this work is to embed a volume density model into a generalized cylinder. The generalized cylinder is used to specify the envelope shape of a hair cluster. The detail of the hair is then modeled by a volume density model in which a randomly generated density map on the hair base is projected into and deformed along the generalized cylinder.;The main advantages of the new model are: (1) it provides a very compact and efficient representation for complex hair shapes; (2) it significantly improves the feasibility and capability for interactive hair modeling and styling; (3) it produces high quality hair images; (4) it provides a multiresolution model for adaptive rendering; and (5) it supports efficient dynamic simulation at hair cluster level.;A rendering algorithm is presented to display the cluster model, based on ray tracing and volume rendering techniques. Several effect enhancement methods are provided to make the final rendered picture more natural and realistic. A hair design system, called V-HairStudio, was developed in our research work, providing a rich set of functionality for interactive design and manipulation of sophisticated hair styles. Furthermore, a new dynamic model for an efficient hair animation is proposed, based on the cluster hair model. |
