Feng Xie, Eric Tabellion, Andrew Pearce. Soft Shadows by Ray Tracing Multilayer Transparent Shadow Maps. In Jan Kautz, Sumanta N. Pattanaik, editors, Proceedings of the Eurographics Symposium on Rendering Techniques, Grenoble, France, 2007. pages 265-276, Eurographics Association, 2007. [doi]
Abstract is missing.