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Common 3Delight-specific attributes for all Maya lights.
Exposure
This is an additional control over standard light's intensity. Exposure is in many cases the a preferred control due to it's likeness to photography. Final area light intensity is then computed:
I = intensity * pow(2, exposure)
Diffuse Contribution
Attenuates light source intensity for diffuse rays.
Specular Contribution
Attenuates light source intensity for specular rays.