Cryptomattes are't saved properly

[koltscho]

Hello!

I am having problems saving cryptomattes. When I look at the cryptomatte pass in render window everything seems fine. But once I save it I am getting just a green image. I tried in 2018.1.1 and 2018.1.2 . Tried in Standalone and tried it from Houdini. I might be setting something wrong in export settings. I am using 32bit exr , untonemapped (tried tonemapped as well). Tried multilayer exr and also separate passes. Nothing seems to work.. Can anyone share some settings that work? Thank you.

[carmichael84]

What are you previewing the green crypto pass in? You typically need a plugin to process the cryptomatte.

You can get the Nuke / Fusion ones here:
https://github.com/Psyop/Cryptomatte

and the After Effects one from here:
https://www.fnordware.com/OpenEXR/

(should be in the bundled ProEXR zip file you can download there)

Not sure if that's your issue, apologies if I'm just stating the obvious

[koltscho]

Hi carmichael84,
thank you for the reply. Unfortunatelly I tried opening in Fusion and also in Photoshop with EXR- IO plugin. Both times they vere green. I am pretty sure that they would open fine if something wasn't wrong. But if anyone has a cryptomatte .exr I could try just to be sure I would love to try. I wasn't able to get my hands on any.

[richardyarlett]

I am having the same problem. Octane 2018 in 3dsmax is just generating empty bright green data...... WFT

[richardyarlett]

This is what I am getting as well

[richardyarlett]

Ok figured it out and I cannot believe the answer.
You have to render a at MINIMUM number of samples which is equal to "bins" x "seed factor" for the cryptomatte data to show up and be valid.

So
rendered samples >= bins x seed factor.

If you are even 1 sample below it does not work.

For example if you want 4 bins of 15 samples per bin you have to render at least 60 samples for it to work.