A Particle Modeling for Rendering Irregular Volumes

In this paper, we describe a particle modeling technique for rendering irregular volume datasets. It is well known that the memory bandwidth consumed by visibility sorting becomes the limiting factor when carrying out volume rendering of large irregular volume datasets. Previously we proposed a volume rendering without the visibility-sort, which represents a given irregular volume dataset as a set of opaque and emissive particles and projects particle into sub-pixels. In our original technique, the resulting image cannot be comparable to the volume ray-casting image with an adequate sub-pixel size since the size of a particle was not explicitly specified. To solve these problems, we introduce a particle size which is identical to the sub-pixel size to estimate the accurate particle density. To confirm its effectiveness, we applied our proposed technique to large irregular volume datasets, and made clear that the image quality is improved with the decrease of the particle size, theoretically and experimentally.