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Cryptomatte - File Output node is messing up the multilayer exr, so blender cryptomattes are not working in the compositing app Blackmagic Fusion 9.
Open, Confirmed, LowPublic


System Information
Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 419.35

Blender Version
Broken: version: 2.80 (sub 71), branch: blender2.7, commit date: 2019-05-20 22:03, hash: rBe78770039397
Worked: (optional)

Short description of error
Cryptomatte - File Output node is messing up the multilayer exr, so blender cryptomattes are not working in the compositing app Blackmagic Fusion 9.

Exact steps for others to reproduce the error
Open the attached blend-file.
Hit render animation.
Two files are generated within the tmp folder.
One from the compositor file output node (Cubes_Cryptomatte_test_FileOutput_0001.exr)

and one from the core output in the output properties (Cryptomatte_Cubes_test_0001.exr).

As you can see on the filesize of these multilayer exrs, they are not the same, but should?!
If you try to use the cryptomatte channels in these files in the free compositing app Blackmagic Fusion 9 only the cryptomattes frome the one, which wasn´t save though the file output node, works correct.

Is the file output node in the blender compositor changing something in the multilayer exr?

In Fusion Cryptomatte_Cubes_test_0001.exr - The Channel IDs are recognized by Fusion.

In Fusion Cryptomatte_Cubes_test_FileOutput_0001.exr - The Channel IDs are not recognized by Fusion.

The error message whithin Fusion.


To Do

Event Timeline

fusion cryptomatte plugin is trash generally... i had problems with cryptomatte from clarisse and also from houdini with fusion.. if the project is a bit bigger it simply don't work anymore.

Yes maybe the plugin in trash but I think the fileoutput in blender should be the same, if you use a fileoutput node or not.
Comparing the metadata or the exr-header may show what is different amongst the two outputs.
Otherwise if you have many renderlayers you are not able to render them into different files if you want to use cryptomatte in another compositing app.
Look into this thread
People have problems using cryptomattes from blender cycles in all the other compositing apps (Nuke, After Effects, Fusion).
Sorry, but the blender compositor is no alternative if you want to make highend compositing.
Today I testest cryptomattes from blender in After Effects. With the free ProEXR 2.0 Plugin it works fine but I need a node base compositing software.
I also tested Natron. The cryptomatte implementation in Natron works, but if you use aspecific nodes like glow together with the cryptomatte keyer, it crashes.
There are sample files from the cryptomatte inventor Psyop, which you can download from their githup page together with the cryptomatte plugins for nuke and fusion and they work fine.
So something is wrong with the blender cryptomatte implementation, maybe not following the standard as thought by Psyop?

yeah i agree that meta data shuld have VFX standard and be same in both case. However i don't agree about compositings apps in general.. For me, the best is Nuke.. after that is Blender and very last is Fusion, that on big projects just chokes and generally performance is bad and anoying. it is mostly designed to work with TV stuff. not CGI. However it do have neat color gradeing tools.

Nuke maybe the best, its industry standard I know and I would love to work with it, but my company can´t afford to pay nearly 4000€ per license.
Fusion 9 is free and Fusion 16 Studio is only 320€.

Nuke is worth the money. Working in fusion is slow as hell, i wouldn't be suprsied if nuke artist would do job 2 times faster and better.

Please keep on topic. Cluttering this site with non related information will not make us solve issues faster.

Not sure, but might be related to T63270?

My problem is as mentioned in the description, that if I use a file output node in blender the cryptmatte informations in the multilayer exr change, so they can´t be read by the compositing app Fusion.
If I render without an output node, everything works fine in Fusion.
So my assumption is that the file output node changes IDs or metadata?!

Jeroen Bakker (jbakker) triaged this task as Confirmed, Low priority.Thu, May 23, 3:49 PM

Crypto matte meta data related to the naming of the layers. The compositor does not support meta data of render layers, or any meta data at all.
We should come up with a good design if we want to support using blender compositor for this.

Will put this as a TODO as it is currenlty not designed or implemented to support this.

Jeroen Bakker (jbakker) changed Type from Bug to To Do.Thu, May 23, 3:49 PM

If you have viewlayers, the file output node is the only way, to render them to different multilayer exr´s.
Otherwise every viewlayer and pass ends up in one multilayer exr. If you have to rerender one viewlayer, you are produceing new content not able to delete old renderings wihtin the multilayer exr.
In Blender it is then also not possible, to write only cryptomatte to a seperate exr-file, because without the file output node the combined pass is always written to file.
For me the FileOutput Node is very important when rendering viewlayer! Otherwise you have to render every viewlayer after each other, setting new output settings after each rendering. Thats not very efficient!
Is it not possible to make the fileoutput node the same behaviour than the regular output?