...

The tokens for these events are are R and T as shown above. You may specify which you want to collect or both. Later we will discuss some shorthand for specifying either but for now we'll use the tokens. Light that is absorbed is handled by the material itself and since it doesn't travel back into the scene (its energy absorbed like light in the real world) we don't collect it.

Below is a beauty render and the diffuse transmission effects rendered alone in an LPE. This includes translucency and subsurface scattering.

Scattering Events

A scattering event is light scattered from a reflection or transmission. In RenderMan we provide two events and one special User event:

...

There is a funny thing about specular objects without diffuse shading, they only look like the things they reflect. If you were to render the Cornell Box scene examples with perfectly specular surfaces and a light, all you would see are reflections of the light. What does a mirror look like? Can you describe a mirror that has nothing to reflect? Or does the mirror look like what it's reflecting? This is why indirect results are so important for realism and ray tracing.

A diffuse scene using subsurface and translucent (both called diffuse transmission) effects.

A diffuse specular scene using subsurface and translucent effectsiridescence and transmission (glass).

A specular scene using iridescence and transmission (glass)