An Integrated System for Modeling, Animating and Rendering Hair Agnes Daldegan Nadia Magnenat Thalmann MIRALab, University of Geneva, 24, rue du Général-Dufour CH-1211 Geneva, Switzerland Tsuneya Kurihara Central Research Laboratory, Hitachi, Ltd Kokubunji, Tokyo 185, Japan Daniel Thalmann Computer Graphics Lab, Swiss Federal Institute of Technology CH 1015 Lausanne, Switzerland Abstract There are basically four problems to solve in order to produce realistic animated synthetic actors with hair: hair modeling and creation, hair motion, collision detection and hair rendering. This paper describes a complete methodology to solve these basic four problems. We present how hair styles may be designed with our HairStyler module. Then we survey the animation model and emphasize a method of collision processing. Finally, we explain how hair may be rendered using an extension of a standard ray-tracing program. We also show applications of our synthetic actors with various hair styles and different styles of mustaches and beards. Keywords: hair modeling, animation and rendering, sculpting software, dynamics, shadow buffer Introduction In the field of human simulation, hair presents one of the most challenging problems and therefore has been one of the most unsatisfactory aspects of rendered human images to date. The difficulties of processing hair result from the large number and detailed geometries of the individual hairs, the complex interaction of light and shadow among the hairs, and the small scale of one hair's width in comparison to the rendered image. In fact, there are basically four problems to solve in order to produce realistic animated synthetic actors with hair: hair modeling and creation, hair motion, collision detection and hair rendering. Each of the four problems has been addressed by several researchers, but no one has proposed a complete methodology or integrated system to solve the four problems. This paper describes such an approach based on the cooperation of the University of Geneva, the Swiss Federal Institute of Technology in Lausanne and the Hitachi Central Research Laboratory in Tokyo. The first section reviews the four problems and the various solutions proposed by researchers. The second section describes how we model and create hair and hairstyles. The third section explains a method to animate hair with collision detection. The fourth section surveys the rendering method and the last section presents a discussion and future developments