Interactive Algorithm Exploration using Meta Visualization

In volume rendering shadows provide an important visual cue, and enhance depth perception. However, shadowing has its own disadvantages. Shadows do not take into account the importance of features and could potentially result in too dark scenes. In this paper we propose an approach for inconsistent shadowing, which is designed to overcome these limitations. For the purpose of illustrative rendering, we propose two complementary techniques: 1. shadow caster inconsistency and 2. shadow receiver inconsistency. We demonstrate several advantages of the different approaches, using inconsistent shadowing. We present two approaches, based on shadow transfer function concept, an approach, introducing usage of gradient magnitude information in shadowing, and a method for adaptive shading and shadowing of the surface, depending on the gradient certainty.