mixmaterial mask

[mesut]

hi,

first things first: i am not sure, if this is a topic relevant for this plug-in section at all. maybe it is more of a rendercore-topic? nevertheless, i'll go ahead and try:

how would one manage to get masks for different materials that are burried within a mixmaterial? is that possible at all?
here's what i mean:

there is the red diffuse and the blue diffuse combined in a mixmaterial, in this case via checker pattern, but the question is also valid for any other kind of mix-method.
how can i retrieve some mask/layer/whatnot with wich i can grab the red and/or blue part of this render in photoshop and edit that parts in the post?
the matid i found in the passes-section obviously gives me a mask only for the whole mixmaterial.

thx.

[bepeg4d]

Hi mesut,
the trick is to enable Materials Render passes / IOR filter and change one of the material to glossy with index at 8:

ciao beppe

[mesut]

hi bepeg4d,

that's a nice trick! thank you.

i realized that i can additionally utilize the roughness filter for that goal, too.
so that would be two layers of information, each of which can be packed with seperate intensities by choosing different ior- and roughness values. that's some masking that is do-able with this method.

on the other hand, this approach does mean, that i have to go into the mixmaterial and edit every "sub"-material in it in a way, that it has an ior or a roughness to be able to render their masks in a second go (since i would only need to have the masks noise-free i guess i could reduce the sample-level of the inevitable new beauty-pass to a minimum of 1?).

in the above example with the two "sub"-materials that's no issue... having a real-world material composition with lots of seperate elements in it (think brand-label on bottle for example), it's a bit more hand-work.

i guess the fastest approach to this would be:
make a copy of the mixmaterial including all it's sub-materials and edit those accordingly to your concept.
create a take in which newly created roughness/ior-filtered material-comp replaces the original material-tag of the object to be rendered.
use the take system to render the "original" object and the roughness/ior-filtered in two seperate renderings with their according rendersettings.

well, at least that's how i would think of it as the quickest way.
if there's a quicker/more straight forward way of doing such a let's say label-job... i would love to hear.

thx again.