@article{CGF34-3:151-160:2015,
journal = {Computer Graphics Forum},
title = {{Visualization of Particle-based Data with Transparency and Ambient Occlusion}},
author = {Joachim Staib and Sebastian Grottel and Stefan Gumhold},
affiliations = {CGV},
projects = {SCADS},
areas = {areava},
pages = {151--160},
volume= {34},
number= {3},
year = {2015},
DOI = {10.1111/cgf.12627},
abstract = {
Particle-based simulation techniques, like the discrete element method or molecular dynamics, are widely used in
many research fields. In real-time explorative visualization it is common to render the resulting data using opaque
spherical glyphs with local lighting only. Due to massive overlaps, however, inner structures of the data are often
occluded rendering visual analysis impossible. Furthermore, local lighting is not sufficient as several important
features like complex shapes, holes, rifts or filaments cannot be perceived well.
To address both problems we present a new technique that jointly supports transparency and ambient occlusion in
a consistent illumination model. Our approach is based on the emission-absorption model of volume rendering.
We provide analytic solutions to the volume rendering integral for several density distributions within a spherical
glyph. Compared to constant transparency our approach preserves the three-dimensional impression of the glyphs
much better. We approximate ambient illumination with a fast hierarchical voxel cone-tracing approach, which
builds on a new real-time voxelization of the particle data.
Our implementation achieves interactive frame rates for millions of static or dynamic particles without any pre-
processing. We illustrate the merits of our method on real-world data sets gaining several new insights.
}
}