Illumination

Category: mental ray > Light

Shader Family: Light

Output: Scalar

This shader provides a physically accurate lighting model for light sources. This can be gentle and gradual falloff curves for dim lighting, or bright and overexposed central areas of bright lighting.

CG artists often avoid realistic lighting because of its tendency to create areas of overexposure, which often look unnatural due to their hard edges. The Glare shader corrects this problem by creating overexposures that look realistic. You can use Illumination in combination with Glare to achieve natural lighting effects.

Name	The name of the shader node displayed in the render tree. Enter any name you like, or leave the default.
Brightness	A multiplier that allows you to turn-up the light's brightness well past 1, likely causing overexposure in some parts of the image.
No Falloff	The light illuminates all objects with the same brightness regardless of distance.
Real Falloff	Uses the inverse-square law for fall off. Unlike the Linear falloff, Realistic fall off causes nearby objects to be extremely bright, while at the same time distant objects never quite become completely black.
Linear Falloff	The light illuminates all objects with a linear fall off.
Linear Start	Specifies the distance from the light where linear falloff begins.
Linear End	Specifies the maximum distance reached by the light.
Custom Falloff	Specifies a custom curve for the light falloff. From the Start, Mid, and End values the shader approximates a curve that passes through the three points.
Custom Start	Specifies the distance at which the light begins to diminish.
Custom Mid	Specifies the distance at which the light is at half intensity.
Custom End	Specifies the distance at which the light becomes completely black.