This page provides information of the Decay Attributes that can be added to some Maya lights.
Overview
The V-Ray Decay Attributes can be added to Maya Spot Light and Maya Point Light by selecting its shape node and selecting Decay attributes from the Attributes > V-Ray menu. This adds several attributes to that light, which allow you to control the V-Ray Decay parameters of the light. The Decay parameters determine how the light fades in and out. The Near decay determines how light fades in. The light isn't at its maximum value at its source, but instead gradually increases until it reaches the Near decay end. The Far decay determines how light fades out. The light isn't at its maximum value at its end, but instead gradually decreases after the Far decay start.
UI Path: ||Select Light|| > Attribute Editor > Attributes menu > V-Ray > Decay
Decay Attributes
Near decay on – Toggles near decay on and off.
Near decay start – Determines where the fade in starts. Anything before this point is rendered dark.
Near decay end – Determines where the fade in ends. After this threshold, the light is at its full value.
Far decay on – Toggles far decay on and off.
Far decay start – Determines where the fade off starts.
Far decay end – Determines where the light reaches a value of 0, i.e. completely fades off.
