Proper workflow for cryptomatte

[frankmci]

What happens if you cyrptoMaterialNodeName pass? You should have unique material names for so it can match passes by material names.

I'm getting back to this thread a day or two later.

Thanks, Ahmet, that worked. It honestly hadn't occurred to me to try each matte option to see if they behaved differently between renders.

I know you are juggling a lot of balls, but perhaps this very important attribute of the CryptoMaterialNodeName pass can be indicated more explicitly in the interface, as well as included in the Octane docs. There's already a section in the docs for Cryptomatte called IMPORTANT NOTES, and this seems like a good fact to include there.

[BCres]

Yes! Unfortunately, me and team have a lot of things to do. This is unnecessarily long discussion I believe. Without giving enough information and don't try different ways that should be avoided.

Maybe I'm reading your reply wrong, but I was telling people your way works. That they should listen to you.

[BCres]

I re-read it and figure you were agreeing with me. Sorry.

[Padi]

DWAA & DWAB lossy compression has now been fixed to keep cryptomatte lossless inside the same EXR.
viewtopic.php?f=24&t=75100&p=385032#p385032

[Hurricane046]

Just tested CryptoMaterialNodeName and it really outputs different masks for each individual material name on any given geometry. Quite handy, considering this is done automatically.

But what if I have let's say a terrain with hills that have THE SAME material. How do I tell cryptomatte "hey, I'd these two hills in the foreground to be in one separate mask, these three in the back in other separate mask... and so on"?

[bepeg4d]

You can use the CryptoMaterialPinName pass.
it works with polygon material selections, so you can select a specific material of an object with multiple polygon selections and materials assigned:

ciao Beppe

[Hurricane046]

So this only works on objects that are editable? There isn't any option to tell cryptomatte "group this pencil, this monkey and this umbrella together"?

[bepeg4d]

Sorry, I have understood that you were talking about a single landscape object.

If you have several objects with the same material, a solution is to is to use the Take system, to create a different take of the scene.
Then you can set a different Render setting, with the general Kernel set to Max Sampling at 1, avoiding to save the Beauty passs, since it will be calculated bu the first take.
The important thing is to enable the Ignore unused materials option in Render Settings OctaneRender main tab.

Then you can use a different material assignment to define the desired masks, like three diffuse materials named Mask 1, 2 and 3 with different coloring, and enable only the CryptomatteMaterialNodeName pass.

In this way, you end up with the desired Cryptomatte mask passes.

ciao Beppe

[Hurricane046]

Well we're trying to achieve this desired "grouping" in one render. Beauty + all the desired masks in crypto. Using ocol with red, green and blue channels doesn't give you that many groups to work with.

So far I haven't found a way to tell crypto "yo, group these 5 objects for me into one mask and these 13 objects into another mask and so on...". Using CryptoMaterialNodeName is a stable way that doesn't change seed BUT it's not great for many other cases because the user can't group stuff together as he wishes (renaming materials to force a crypto group seems like a crazy way to do it).

[Powel2097]

Hi ,

in the latest 2020.1.2 when enabling cryptomattes I only get transparent images.
Sometimes with edges where the motionblur appears. the rest is transparent.

When switching back to 2020.1.1 it works as expected.

It happens in every scene. Even with a simple box in it.

EDIT:
I just noticed it is also happening in 2020.1