[Source] VRay Guide

This Video will show you how to use VRayOverrideMtl to fix the Color Bleeding or Light Leaks produced as a result of secondary bounce in 3ds Max.

VRayOverrideMtl can fix Reflections, Refractions, Shadows and GI of your original object. Today we are going to examine function GI only. However it is important to notice that you can use this material for fixing any color you want your object to spread / to reflect / or to cast shadow.