Hi, we use a lot of RGB based masks at my studio, so we take advantage of Corona's "CMasking_Mask" element in RGB mode for our objects etc.
Looking at Vantage's documents and forums, they use Vray's "MultiMatteElement" which does the same thing, but it is picked up by Vantage when exporting a render.
I have attached two screenshots. One in vantage showing that it is picking up 0 Multi Matte elements. And an example in Max which shows a CMasking_Mask setup for object IDs 1,2,3.
Is there a better way that I an unaware of that we should be using? Or is this a feature not yet available for live link?