Cryptomatte not working in Fusion

[pscgi]

Hi guys. I've recently started using Fusion and I'd like to start using Cryptomatte for masking. Unfortunately when I save it as .cxr and then change its format into .exr (this is how it should be done according toit doesn't work - when I plug it into Cryptomatte script there are errors saying that no cryptomatte metadata was found. This is what I get from Fusion console:

[Cryptomatte][Cryptomatte1][ERROR] no cryptomatte metadata found
...ion\Reactor\Deploy\Modules\Lua\cryptomatte_utilities.lua:615: ERROR
stack traceback:
   [C]: in function 'error'
   ...ion\Reactor\Deploy\Modules\Lua\cryptomatte_utilities.lua:615: in function 'log_error'
   ...ion\Reactor\Deploy\Modules\Lua\cryptomatte_utilities.lua:695: in function 'get_cryptomatte_metadata'
   ...esign/Fusion/Reactor/Deploy/Fuses/Matte/cryptomatte.fuse:275: in function <...esign/Fusion/Reactor/Deploy/Fuses/Matte/cryptomatte.fuse:251>
Cryptomatte1 failed at time 0

Am I doing anything wrong? Should I do something in between so that Cryptomatte node in Fusion would read it as a proper cryptomatte reneder element? I'd be very thankful for help as using cryptomattes seem to be ultra efficient but unfortunately can't get it to work.

[TomG]

Can you test in Photoshop with IO-Exr? If not, can you upload the CXR to the private uploader so we can take a look?

Can you confirm the workflow and process used to save the CXR - was it "render in the VFB and save to CXR from the VFB" or some other method? And can you share the settings for the Cryptomatte, and in the Render Elements dialog in general? Also which version of Max, and which version of Corona (please be specific there, e.g. Corona 8 Release Candidate 2 etc. as general comments such as "the most recent" doesn't confirm for sure which version it is, as there may be releases you didn't notice, etc.). Thanks!

[pscgi]

Thanks Tom for your quick response. So first of all my Max version is 2022.2 and Corona 8 RC1 but I guess it doesn't matter anymore as I did some tests in the meantime and looks like now it works both in PS and Fusion no matter if I open it as CXR (without changing the extension) or after changing it into EXR. So looks like I was doing it in a wrong way as before I didn't save everything from VFB as CXR, I saved everything but Cryptomatte in EXR and just changed Cryptomatte's render element extension into .cxr in Render Elements tab (so everything was saved as EXR and only Cryptomatte as CXR) and that way it didn't work.

Just one more question - do you know when approximately it will be possible to save it automatically (not manually from VFB) and as EXR?

Edit: Just did one more test and it works in Fusion even with automatic save as CXR so no need to save it from VFB. But still CXR files are much bigger than EXR so it would be great to know when approximately saving as EXR will be possible :)

[TomG]

That's great news that you got it working! At the moment not sure of future plans beyond this initial implementation, we'll have to see how things go (a mix of what gets prioritized for future updates, how many folks use even this version of cryptomatte, and more). All I can say for now is that this will be it for how it works in Corona 8 - beyond that, nothing is known or decided yet!

[pscgi]

And now you made me really sad :) Just kidding but Cryptomatte really looks like a perfect masking solution but unfortunately right now I don't think it can be used for animations as saving eg. 1500 frames in CXR would cause a need to buy new discs for each project. And would't it be possible to make some changes to (temporarily in the near future) make it work by only outputing Cryptomatte render element in CXR and everything else in EXR? I'm not a programmer so maybe such a "small" change would require a ton of programming work but (hopefully) it doesn't hurt to ask :)

[davemahi]

I am also not a fan and I am confused with the CXR file type for this. Was there an explination about why?
I am not sure you will see much adoption of this in workflows, other than for print work perhaps.
But for animation like pscgi said, its going to be hard to use in big animation workflows.