Multi/Sub-object with cryptomatte?

[White Wizard]

Thanks for the video. I think I've discovered the issue.

VrayCryptomatte does indeed render the separate multi-sub-object materials, however it does not apply unique names to them as it does for regular materials.

I replicated your scene and imported the cryptomatte into Photoshop. I can see the materials separated by layers. As mentioned, the sub-object mats do not have unique names.

This causes an issue when compositing within Fusion, as the cryptomatte plugin requires a unique name to be added to a "matte list".

Does anybody know of a workaround or solution to this?

[Vizioen]

Hi Chaos, seems that this should be fixed in Vray 5 Update 1, but I can't seem to make it work?

[theedge]

Any news on this ? I could not get it to work neither.

[pg1]

Not sure with Fusion but gpu in bucket mode works fine with After effects.

Gets wierder though. Works find on Vray 5 update 1 ....sort of.

Make a simple mult mat with 3 materials. Rendering the Multisub object material will all render the same crypto matte.
Go to the second material and under options check the effect ID button and set it to 1.
Now your 1st and 3rd material will be in the same crypto matt but the 2nd material with the effect id changed will be a different color

Now open the compact material editor and change the material id for the 3rd material using the old skool material id flyout thing that only goes up to 15 and pick any number other than 1 (you used it already) and it will render a different cryptomatt color

So you can have cryptomattes work on material node with multi sub objects by changing material ids but it is buggy.
Effect id acts like a boolean and doesnt read the change in id number.
The old max material id works seems a bit buggy

[Vizioen]

Thanks pg1. Can someone from Chaos please respond if the above method is the one we should use? I don't use GPU though, still old skool CPU.

[rasmus]

Cryptomatte on Multi-/Submaterials is not working for me either on max2020 / Vray Next 4.30.02 (cpu) either...?

chaos, (when) will this be fixed or can you share any reliable workarounds?

[JezUK]

I'm having this same issue with multi-sub objects and V-Ray GPU, Cryptomatte etc.

I'm testing via a simple test scene and Maxtree Bush that I'm evaluation via Forest Pack Pro, using 3DS Max 2022.3 and V-Ray 5 update 2.2 and the cryptomatte is missing in my experience the 'middle' Material Ids, ie. not the first or last in a multi-sub object, but the 2nd.

Also, MatID is completely black... (edit: because it's not supported in GPU rendering).

[hermit.crab]

pg1 Vizioen theedge
Both GPU and CPU correctly work with Multi/Sub-object materials on my end, tested with latest official release V-Ray 5. update 2.2. Have you guys set the Cryptomatte ID type to "Node material name"?

Cryptomatte on Multi-/Submaterials is not working for me either on max2020 / Vray Next 4.30.02 (cpu) either...?

chaos, (when) will this be fixed or can you share any reliable workarounds?

The feature was implemented in V-Ray 5.1.1.

[JezUK]

pg1 Vizioen theedge
Have you guys set the Cryptomatte ID type to "Node material name"?

Yes, and for me it doesn't work.

I am using this with Forest Pack Pro and the Cryptomatte only find a couple of the MatIDs in a multi-sub object of 3 materials.

[hermit.crab]

Yes, and for me it doesn't work.

I am using this with Forest Pack Pro and the Cryptomatte only find a couple of the MatIDs in a multi-sub object of 3 materials.

I just tested this with a plant (Crape Myrtle 3 from the Starter Library) and it seems to work- masks are created for each sub-material. There are, indeed, Cryptomatte layers, which are blank. However, the shaders, for which the layer was created were not even used in the asset itself (I'm referring to Mat ID 4, which is not present in any of the polygons of the original mesh). Another layer that is empty is the Multi/Sub-object mtl itself (since it was defragmented into its components). Is this the case on your end? If not - share screencaps and a scene so we can take a look.

[JezUK]

Hi Aleksandar,

I think the best thing is if I send you a simple file - it'll be of a Maxtree model that I tested (because I will need to use this in my scene, it's a Rose Bush and the client wants red roses, not yellow ones) - yes there are several other ways I can do this but first thoughts were to use Cryptomatte and for this simple file, an object with a material with just 3 sub-materials it doesn't work.

Many thanks.

So you know, I'm using GPU rendering and Bucket, and 3DS Max 2022.

I will send an email now.

[JezUK]

Hi Aleksandar,

Support Ticket has just been sent with attachment.

Looking forward to your solution

[hermit.crab]

JezUK Thanks for the provided scene. From the looks of it, the petals and leaves are baked together (check the bitmaps) and used in a single shader. The missing sub-material doesn't seem to be applied at all (in the RGB). Could you check if the original mesh has material id "2" polygons?