A directional occlusion shading model for interactive direct volume rendering

Volumetric rendering is widely used to examine 3D scalar fields Key aspect: provide perceptual cues to aid in understanding the data set Shading models with natural lighting conditions better convey depth information and spatial relationships Traditionally require considerable (pre)computation. Directional Occlusion Shading (DOS) Plausible occlusion effects Qualitatively similar to full ambient occlusion Solid and semi-transparent features interactive change of Transfer function Clipping planes Camera position Global ambient occlusion solution expensive Other methods compute locally spherical occlusion DOS considers all features between a point and the ambient light Restricted to a subset of the sphere Specialized phase function Backward peaked cone User specifiable aperture angle