Interactive Image-Space Volume Visualization for Dynamic Particle Simulations

Particle-based simulation plays an important role in many different fields of science and engineering. Two common visualization approaches for the resulting data are glyph-based rendering and density sampling employing volume rendering. Fine geometric features are inherently captured by glyph-based methods. However, they might suffer from aliasing and the global structure is often poorly conveyed. Volume rendering preserves the global structure but is limited due to the sampling resolution. To avoid aliasing artifacts and large memory footprints, we propose a direct volume rendering technique with on-demand density sampling of the particle data, as combination of splatting, texture slicing, and ray casting. We optimized our system with a novel ray cast termination employing early-z-test culling and hardware occlusion queries utilizing inter-frame coherency. Our system contains a fully-featured volume renderer and captures all geometric features of the data set representable at the available display resolution. Since no pre-computation is required, the proposed method can be used easily to visualize time-dependent data sets. The effectiveness of our approach is shown with examples from different application fields.