Progressive Photon Beams with Adaptive Free Path Sampling

Abstract

Photo-realistic rendering of participating media, such as steam, water, fire, and smoke, is an important research topic in the computer graphics field. We present a fast and physically based method for rendering participating media based on the progressive photon beams method. For this, we propose a new version using adaptive free path sampling technique and applying a new estimation method for light transmittance functions based on stratified sampling, which overcomes the deficiencies in the progressive photon beams method. Our method is able to take into account not only single but also multiple scattering of light inside the participating medium. Using our method, participating media with complex density distributions can be handled, as well as complex lighting conditions. Additionally, we can obtain images which are guaranteed to converge to exact solutions. Moreover, our method is implemented on a GPU, enabling fast computation of the solutions.