Abstract
In computer graphics, simulation of natural phenomena is one of the most important research topics. In this paper, we focus on the rendering of dynamic clouds. To create realistic images of clouds, the multiple scattering of light inside clouds has to be taken into account. However, this increases the computational cost significantly. To address this problem, we propose an example-based method for the efficient computation of the multiple scattering. First, in a preprocessing step, a set of example clouds are generated and stored as a database after computing the multiple scattering. Then, in a rendering process, intensities of clouds with an arbitrary density distribution are calculated efficiently by refering the precomputed database. The important feature of our method is the ability to calculate the intensity very quickly, even if the density distribution of clouds, the viewpoint, and the direction of the sunlight all change. The time-consuming database construction process does not need to be repeated for these changes. We demonstrate that our method is more than tens times faster than the previous methods.
