Volumetric ray tracing

This paper presents an efficient ray tracing method for scenes containing volumetric as well as geometric data. A global illumination equation is developed for this method, which is able to capture in a single image both realistic effects and practical volume rendering. In this method, ray-object intersection calculations result in standard intersection points, as well as intersection segments. For accuracy and efficiency, all objects along a ray are sorted according to distance and intersection classification before any intersection calculations are performed. The intersection results are then passed to a shader, which evaluates the intensity equation defined by the illumination model to determine the final pixel value.