Practical Real-Time Hair Rendering and Shading
We present a real-time algorithm for hair rendering using a polygon model, which was used in the real-time animation Ruby: The Double Cross, appearing in this year's SIGGRAPH animation festival. The hair shading model is based on the Kajiya-Kay model, and adds a real-time approximation of realistic specular highlights as observed by Marschner et al. We also describe a simple technique to render the semi-transparent hair model in approximate back-to-front order. Instead of executing a spatial sorting step on the CPU at run-time, we render the opaque and transparent hair regions in separate passes to resolve visibility.