Ropinski,T., Kasten,J., Hinrichs,K.
GPU-based raycasting has evolved to be the defacto standard for interactive volume rendering on off-the-shelf graphics hardware. While in theory this technique can be easily extended by introducing shadow feelers in order to support shadows, this obvious approach has a major performance impact. In this paper we will discuss shadowing extensions for GPU-based volume raycasting and compare them according to their quality issues as well as their performance. In particular, we will compare shadow rays, shadow mapping and deep shadow maps. For each technique we will discuss the implementations, with respect to current graphics boards, and we will compare the visual results as well as the runtime behavior.