Zhang, YuboMa, Kwan-LiuKwan-Liu Ma and Giuseppe Santucci and Jarke van Wijk2016-06-092016-06-0920161467-8659https://doi.org/10.1111/cgf.12916https://diglib.eg.org:443/handle/10Existing real-time volume rendering techniques which support global illumination are limited in modeling distinct realistic appearances for classified volume data, which is a desired capability in many fields of study for illustration and education. Directly extending the emission-absorption volume integral with heterogeneous material shading becomes unaffordable for real-time applications because the high-frequency view-dependent global lighting needs to be evaluated per sample along the volume integral. In this paper, we present a decoupled shading algorithm for multi-material volume rendering that separates global incident lighting evaluation from per-sample material shading under multiple light sources. We show how the incident lighting calculation can be optimized through a sparse volume integration method. The quality, performance and usefulness of our new multi-material volume rendering method is demonstrated through several examples.KeywordsGlobal illuminationhigh performancemultimaterialmultiple scatteringsoft shadowvolume renderingI.3.7 [Computer Graphics]Three Dimensional Graphics and RealismI.3.8 [Computer Graphics]Applications10.1111/cgf.12916401-410