Can you guys please add in material EffectID as a method for selecting what gets used in a selective render
even a combination of EffectIDs would be uber handy
that way can render select, trees + plants
people + cars
etc etc without having to merge in massive amounts of xrefs
can also pretty please get a render element that just specifies the Effect ID as a single white mask
so we dont have to conflate everything into a 3 channel multimatte layer
makes mask selection in photoshop easier.
From a developer point of view: I believe it is not possible, because each material/map decides during evaluation which material effect ID is present. So the renderer needs to actually render/evaluate the map/material to know the material effect ID. It could be different for each pixel/sample of a material.
In case that is not obvious, you could just put the same ID 3 times and get a grayscale mask. Or maybe use psd-manager to split the MultiMatte element into 3 PSD layers/channels automatically.
Daniel
You mean for the render mask? We can put the Object ID there, but the material ID, as Daniel pointed out, would be slower.
Best regards,
Vlado
What about just a specific material? I often get revision just to change a material in scene to a slight different one, like dark wood to medium medium wood, it would time instead of re-rendering the entire scene.
I also would like if the “selection” mode takes refraction into consideration meaning if I select mesh behind a refractive one I am able to render that refracted mesh. I know this would propably mean having to render the refractive Object, too. Maybe do this automatically?
A specific material, if it is a top-level material (i.e. directly applied on the object, and not part of Multi/Sub-object etc) is possible. Will have to think about it.
Best regards,
Vlado
You should be aware that changing certain material properties will affect much more than just this material. If you get a dark wood instead of a light one on your floor the GI solution would be different aswell as the reflections. Having VRay detect where the material is reflected and render that portion too would be incredible, but I guess then you would have to render the whole stuf anyways 
+1 on this one 
Yup, that’s true. However, for quick previews, it would still be very useful !