Interactive Dynamic Volume Illumination with Refraction and Caustics

Abstract

In recent years, significant progress has been made in developing high-quality interactive methods for realistic volume illumination. However, refraction - despite being an important aspect of light propagation in participating media - has so far only received little attention. In this thesis, we present a novel approach for refractive volume illumination including caustics capable of interactive frame rates. By interleaving light and viewing ray propagation, our technique avoids memory-intensive storage of illumination information and does not require any precomputation. Propagation of refracted illumination is realized by employing a Semi-Lagrangian backward integration scheme, inspired by texture advection from the field of texture-based flow visualization. It is fully dynamic and all parameters such as light position and transfer function can be modified interactively without a performance penalty.