Vray 3.6 cryptomatte does not work with DWA compression

[sharktacos]

Vray 3.6 cryptomatte does not work with DWA compression. This is easy to reproduce. Cryptomatte works fine on a multichannel EXR with ZIP scanline compression, but not with DWAA or DWAB compression. That is, it is not possible to select the objects in Nuke with the Cryptomatte plugin when the image is rendered with DWA compression.

I'm wondering if there might be a workaround to this involving renaming the channels possibly?

[sharktacos]

I'm guessing that the problem is that the channel is named cryptomatte.R cryptomatte.G cryptomatte.B and thus it gets lossy compression, rather than getting ZIP or RLE... I'm thinking it probably should get RLE like the alpha does.

[sharktacos]

Giving this a friendly little bump. Nightlies maybe?

[vlado]

It is on the "to do" list and will be fixed at some point. It is a bit tricky to tell the DWA compressor of the OpenEXR library what to compress and what not though.

Best regards,
Vlado

[sharktacos]

Thanks Vlado, In case you haven't seen this, perhaps this is helpful:
https://github.com/Psyop/Cryptomatte/issues/35

From what I see there, if the cryptomatte was output with the suffix .XYZ (cryptomatte.X cryptomatte.Y cryptomatte.Z) instead of .RGB (cryptomatte.R cryptomatte.G cryptomatte.B) it should get ZIP compression rather than lossy.

[vlado]

I don't think we will rename the elements. Rather we will patch the OpenEXR library to do what we need.

Best regards,
Vlado

[sharktacos]

Cool. If you could please update this thread once this is in the Nightlies that would be super awesome.

[Paul Oblomov]

Yea, would be great, we're trying to work 4k, and without dwaa it is useless

[sharktacos]

I know Chaos has fixed this by modifying the EXR format. Has that been put into Nightlies yet?

[vlado]

It turned out to be more complicated (as usual). If we modify the writer on our end, the resulting OpenEXR files will not be readable by other software. So the other solution would be to name the elements differently (not .R, .G, .B but f.e. .red .green .blue) and make sure that the Cryptomatte gizmo works with them. Working on it...

Best regards,
Vlado

[sharktacos]

Cool, thanks for the update Vlado

[sharktacos]

By the way, I think it should work to name the elements .r, .g, .b (lowercase) instead of .red. .green, .blue if that is any easier.

https://github.com/openexr/openexr/b...ssor.cpp#L3135

[vasil.minkov]

Hello,

Cryptomate + DWA should work in the latest nightlies. Renaming channel suffixes did the trick.

Best Regards,
Vasil

[Jimmi]

Hello,

Cryptomate + DWA should work in the latest nightlies. Renaming channel suffixes did the trick.

Best Regards,
Vasil

Hey Vasil.
Just a heads up, there has been no new nightlies for Maya since the 10th, and as far as I can see that one didn't contain the changes.

[Mihail.Djurev]

Hey Vasil.
Just a heads up, there has been no new nightlies for Maya since the 10th, and as far as I can see that one didn't contain the changes.

Sorry for the confusion, should be available in tomorrow's nightly build.