Octane object tag on polygon selection

[punchin]

Hi All
I was wondering if it was possible to add object tag ids to an object we bought on TurboSquid that has shaders placed onto polygon selections of 1 object?
I need to have each shader with a separate id.

[aoktar]

You can't assign because it's for objects not for polygons. You can use MoGraph color shader for that.

[TonyBoy]

You can however assign different materials to Selection Sets in the usual way.

[ceen]

You get a color mask matte for every material when rendering out a Material ID channel with multipass rendering. But be aware of the fact that Octane has an inbuild random function for the Material ID pass switching the colors of the mask randomly from rendering to rendering. That kills your workflow in compositing because it can happen you ahve to readjust you color masks in comp after every rendering. There are threads on this forum that show the problem and possible workarounds like here:

viewtopic.php?f=30&t=61646

[punchin]

This is the problem I have.
3 cars in a scene the other 2 have a setup with individual objects, the 3rd has shaders on polygon selections.
I am not sure how the mograph shader works with regards to masks.
Is there no shader specific way to get masks like in the object tag.
I have always used the Object color ID and the ObjMaskID but never understood the use of this MatId. I combine in nuke.
how do you use it? with a keyer? keylight or primatte. seems like more work than an RGB or normal ObjMask.

[aoktar]

I got wrong what you want, sorry! Probably the easiest way is to separate your model to objects and apply different ids by object tag.

[punchin]

I thought it might be easier to just separate the objects. I do think that Octane falls short when it comes to masks. I do lots of car commercial work so need masks for every material on the car, the layer mask system with post layer mask samples isn't optimal.
I used to work in Vray and really miss the multi mats( multiple RGB masks) that work through refractions. Perfect for clients that like to have changes inside a car's headlights!!
Or Redshifts puzzle mats.. basically a shader based mask option.

[aoktar]

I thought it might be easier to just separate the objects. I do think that Octane falls short when it comes to masks. I do lots of car commercial work so need masks for every material on the car, the layer mask system with post layer mask samples isn't optimal.
I used to work in Vray and really miss the multi mats( multiple RGB masks) that work through refractions. Perfect for clients that like to have changes inside a car's headlights!!
Or Redshifts puzzle mats.. basically a shader based mask option.

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