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Rendering with Arnold in CINEMA 4D using the C4DtoA plug-in.
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Cryptomatte in Arnold 6

Message 1 of 13
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Cryptomatte in Arnold 6

Hey everyone,

I'm trying to setup cryptomatte in C4DtoA in Arnold 6 - but I'm not being able to install it or at least seeing it under the node list.

I've downloaded these files on the link below (even though there is no bin folder in there as it says on the Description file). And copied it to my shaders and Arnold folder.

I've also downloaded this project file.

But it says I don't have cryptomatte.

I can see these AOV's on my IPR but they are empty (don't show on the exr when opened in after effects / cryptomatte plugin).


I'm not sure if I'm doing something wrong of this is not supported on the new version of Arnold?
I also can't install AL shaders 2 (I managed to do it a few years ago on an older version of Arnold.)

Thanks a lot in advance,
All the best

Joao Monteiro

Labels (4)
Message 2 of 13

Cryptomatte is included with Arnold.

What you downloaded will cause a conflict and problems, so you can remove that.

You have to add the cryptomatte shader to the AOV Shaders in the Render Settings.


// Stephen Blair
// Arnold Renderer Support
Message 3 of 13

Ohhh brilliant, no wonder why I couldn't find much info about how to install it. Thanks Steph, I'll reinstall C4dtoA again and will then import the shader in there. I'll let you know how it goes.


Message 4 of 13

You can click on Arnold > Utilities > Setup cryptomatte in the menu which will add everything you need to use cryptomatte.

Message 5 of 13

Hi @Stephen Blair,
Thanks so much for the help.
This is now working!!

Of course I ran into a different problem and maybe you can help.

When rendering with team render now, on the other machine it fails.
If I render locally with crypto it works, if I render over team render with crypto deactivate it works. I'm using both Mac OS. I'm also rendering image sequences.

I'm on c4d r23 and Arnold 6.1.

I get this error on the my second machine.

[c4dtoa] 00:00:00 4197MB ERROR | [driver_exr] /-----DRIVERS------/CRYPTOMATTE: can't create file "/Volumes/Filepath/SH01-SH05/SH01-05_crypto_.0168.exr": Could not open "/Volumes/File path/C4D Renders/Final_Sequences/SH01-SH05/SH01-05_crypto_.0168.exr" (File output failed.)

2020/12/04 13:26:14 (Error) Render-Job failed: Saving failed.

2020/12/04 13:26:14 Peer-to-Peer Statistics:

> localMachine. Download-Speed 41.21 MiB\s (3x)

Peer-to-Peer Statistics End

I've searched the forum, and found this post from @Peter Horvath, although it's not conclusive or at least to my knowledge.

Message 6 of 13

You are rendering an animation, right? Because, unfortunately, Arnold drivers don't work with single-frame Team Render at the moment.

Is that path correct on the machine? Does it have proper permission to write there?

Message 7 of 13

Hi @Peter - Yes I'm rendering image sequences.

As soon as I disable to Cryptomatte Driver - team render works.

See attached setup.

I've got my main AOV's (DRIVERS) and I've added a separate one for the cryptomatte output as I was having trouble when having it merged in After effects (like this it works).




Message 8 of 13

Make sure the path you set in the driver is available on the client machine. Unlike the native c4d output, Arnold drivers write the file on the client machine when the frame is rendered.

Ideally you have a network drive mounted to the same path on each client.

Message 9 of 13

If it differs, is there any solution to have both?
Can I override the path location in the other machine?

I think it might be it, as the second machine is accessing the volume through the network.

I was trying to follow this but unfortunately I don't understand how to do this and what apps to use.


Message 10 of 13


/Volumes/Lacie 2BIG 6TB/MONDI STUDIO/02_Client Projects/HOCUSPOCUS-UNILIVE/02 C4D/C4D Renders/Final_Sequences/SH01-SH05/SH01-05_crypto_.exr

Secondary Machine:

smb://apple’s Mac Pro._smb._tcp.local/MONDI STUDIO/02_Client Projects/HOCUSPOCUS-UNILIVE/02 C4D/C4D Renders/Final_Sequences/SH01-SH05/SH01-05_crypto_.exr

Message 11 of 13

The only solution currently is using environment variables.

  1. Set the path in the driver as $MYFOLDER/SH01-SH05/SH01-05_crypto_.exr
  2. Set the environment variable MYFOLDER on both machines:
    1. MYFOLDER=/Volumes/Lacie 2BIG 6TB/MONDI STUDIO/02_Client Projects/HOCUSPOCUS-UNILIVE/02 C4D/C4D Renders/Final_Sequences
    2. MYFOLDER=smb://apple’s Mac Pro._smb._tcp.local/MONDI STUDIO/02_Client Projects/HOCUSPOCUS-UNILIVE/02 C4D/C4D Renders/Final_Sequences
Message 12 of 13

Here's a guide of how to set environment variables:

  1. Open the Terminal
  2. Edit bash_profile: nano .bash_profile
  3. Add this line: export MYFOLDER=/Volumes/Lacie 2BIG 6TB/MONDI STUDIO/02_Client Projects/HOCUSPOCUS-UNILIVE/02 C4D/C4D Renders/Final_Sequences
  4. Restart
Message 13 of 13

NOTE: I noticed that recent Cinema 4D versions automatically correct the path and does not allow $MYFOLDER at the beginning. This is really annoying. I have to ask MAXON if this can be turned off. Currently you cannot use env vars because of this. I guess you have to wait for a new build to make this work.

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