Object mask that takes into account reflections and refractions

[CGteam]

Hello! I'm looking for the best way render out a mask of an object and it's reflection/refraction on the surroundings. I want this mask to take object's colour reflecting and refracting through the environent into consideration. I know that there's a way to achieve a similar effect in Corona with propogate in reflections and refractions, but I can't find a way to do this in Vray.


Let's say, I want to have the ability to recolour the red ball to any other colour, but I also want to be able to affect the red reflecting on the ground and on the other balls.


What I'm trying to achieve:

• A mask of one object's colour and it's affect on the scene
• Recolouring the object in max and re-rendering is not an option
• There's only one object/material that I want the mask to show

[hermit.crab]

You need to set the reflection/refraction "Affect channels" option in the VRayMtl to "All channels".