Real-Time Rendering of Cloudy Natural Phenomena with Hierarchical Depth Impostors

This paper presents a real-time method to realistically render dynamic participating media under changing lighting conditions. In order to cope with performance requirements, the volume is built of instances of particle blocks. The simulation and rendering happen on two levels, on the block level and on the volume level. On the volume level blocks are replaced by depth impostors, which allows for very fast recalculation of the cloud illumination. Including depth information into block impostors our technique also eliminates billboard clipping artifacts when the participating medium contains objects. The proposed method can render swirling clouds and smoke on high frame rates, and can be used in real-time applications.