This operator creates a smooth roll-off of the input color from the center of the geometry to the edges, based on the surface normal.
Common uses of this operator include the simulation of clouds and
particle smoke. Usually, in the Surface context, you will pipe the
result of this operator into the Opacity (
Of) input of the Output Variables
Operator, and will multiply it by the incoming color to obtain the final
The Base Color parameter defines the initial surface color. The Edge Falloff determines how quickly the edges fade to black.
No lighting calculation is done in this operator, so either pipe the resulting color into the Diffuse (and Ambient) inputs of the Lighting Model operator, or ensure that the incoming color is pre-lit.
If the Surface Normal (
N) and Incident Vector (
I) inputs are not
connected, the global variables by the same name will be used instead.
Typically, you will not touch
N unless you had applied additional
displacement to the surface using an operator such as Bump Noise. If you
do need to access the global variables directly, they are available from
the Global Variables operator.