Displaying Caustics in the Render
uses Mental Ray (which supports photon
mapping) to render scenes. Caustics can be displayed in the
render pass by selecting caustics in the photon tab of the Render
Options Property Editior. Mental Ray renders the effects using the
mapping technique and various options can be adjusted at this
point to control effect of the caustics at the rendering stage.
Selecting caustics activates the rendering of indirect
illumination only for caustic effects. Illumination only occurs for
photons which follow the path of a caustic, that is, only for
specular reflections and the transmission of light onto diffuse
surfaces. Also because caustics are treated as a separate form of
illumination by Mental Ray activating the global illumination
section only will not produce any caustic effects.
opposite is rendered with both the global illumnination and the
caustic effects activated in the render pass. In the render options
box it is possible to adjust the effects at the rendering stage with
the accuracy, radius and filter controls. In order to get a
precisely detailed effect a high accuracy value must be combined
with a small radius.
Increasing the number of photons in the
scene will result in the effective radius becoming smaller as Mental
Ray does not have as much distance in which to search for photons.
To decrease the grainy appearance without blurring the detail
adjusting the number of photons in the scene light property editor
will be more effective than only adjusting the render pass options.