This page gives some basic details about the Reflection Glossiness render element and how it is used in compositing.
Overview
The Glossiness Render Element stores the image's reflection glossiness as a grayscale image that represents the degree of Reflection Glossiness set for materials in the scene. White areas have the most reflection glossiness, while dark areas have little.
The amount of reflection glossiness for a material is set by its Reflection Glossiness parameter. For example, the V-Ray Material has a Reflection Glossiness parameter, and the Skin Material has parameters for primary and secondary reflection glossiness.
UI Path
||out Network|| > V-Ray Render Elements node > V-Ray > Render Channel > Glossiness
Attributes
Name – The text added to the end of the rendered file, when saved as a separate file (e.g. myrender.Glossiness.vrimg).
Filtering – Applies the image filter to this channel. Image filter settings are in the AA sub-tab of the Sampler tab of the V-Ray Renderer node.