Hey community!
With the release of Corona 1.3, I hoped that finally materials IDs of sub-materials would be detected by CMasking_masks… see the attached pic: I need that plastic, print and the silver band on the top left appear on different masks. But they do not 
In Vray I could get separate masks and that was super useful in compositing.
Am I the only one to be annoyed by this issue? For me it’s very important!
Any suggestion to obtain the masks…?
Thank you!
Hello romullus, thanks for answering!
In your example, you’re working with a Multi/Sub-Object material, while I am interested in separating materials assigned with a blend… my materials don’t follow polygons.
Did you try CShading_SourceColor ? Maybe that would do the job?
I just tried it, but it’s not good in all scenarios!
I have a workaround with light materials, but a separate render is needed in order to calculate the masks. It’ annoying and time-consuming.
Am I the only one in need of this kind of masks…?
For me it’s fundamental for fine tuning of colors and reflections with the client…
I am amazed by the fact that just one person interacted with this topic. How can you do serious post-processing without masks working properly?
…I think it’s currently the biggest flaw in Corona. Please, developers, answer me… will you fix it? I don’t think it requires much effort to repair it!
Best,
ignicapillus
Maybe the problem is that it’s not entirely clear what it is exactly you’re doing. You have a blend material controlled by an alpha? And you want to use the MtlIDs of these submaterials to appear in the render element?
You perfectly explained my intentions 
When the blend material has MtlID=0, Vray makes submaterial IDs appear in the render element.
When the blend material has MtllD different than 0, it overrides the IDs of submaterials.
So this should probably better be placed into the feature requests forum
