This operator simulates a translucent material such as glass, and returns the combined color, opacity, and alpha.
The index of refraction (
eta) is the most important parameter because it
controls the amount of the transmission (ie. refraction) of the surface.
Its neutral value is 1. The environment color is ignored unless you
specify a valid environment map. The reflection bias is used to help
eliminate self-reflection, and is typically a small number.
In order to prevent the renderer from computing standard transparency (i.e. non-refracted transparency), as is the case with glass-like surfaces, the opacity is set internally to 1 to make the surface "opaque".
If the Position (
P) input and the Normal (
N) input are not connected,
the global variables by the same names will be used instead. Typically
you will use Rest Position or UV Space Change as inputs for
will not touch
N unless you want to apply additional displacement to
the glass surface using an operator such as Bump Noise. If you need need
to access the global variables directly, they are available from the
Global Variables operator.