[Paper]2011/11/05

A Multidimensinal Occlusion Shading Model for Direct Volume Rendering

 

In the Directional Occlusion Shading Model, because of the backward-peakedproperty of the cone phase function,

the light direction has to coincide with the viewing direction. However, in this paper, it enables the flexibility of positioning

lighting source with little performance penalty by tilting the cone phase function, that is, changing the light scattering direction.

As a result, the original symmetrical disk-shaped Guassian kernel used to simulate Ambient Occlusion Effect is changed to an ellliptical kernel.

In order to facilitate the computation, the elliptical kernel is stored in a texture map, updated when the corresponding lighting parameter changed.

Compared with the original Directional Occlusion Shading Model, it needs small modification and produces more visually reaslistic effect.

 

Comments

 

What will happen when the lighting direction is opposite to the viewing direction? In this condition, the slices have to be composited in back-to-front order.

If the volume has high density, then it may look very dark since the light has to transmit from back to front.