Cryptomate doesn't work in Nuke 14 / max 2024 / latest arnold

[hyperviktor]

Any scene I render with cryptomatte , the crypto layer shows up in nuke, but the cryptomatte keyer can't see it.

It's with any scene from max 2024 / latest arnold, so no need to share any of my specific scenes, happens in any n ew scene.

I am using ACES color management.

The crypto keyer in nuke shows black and layer selection is locked.

I have checked older renders in nuke, it can see crypto in those, so nuke works fine.

Any solution for this  ?

[hyperviktor]

seems like this so called 'community' is dying. I need some answers, anyone experienced a similar problem ?

[osukas]

I use a lot max 2024 but with MAXtoA 5.6.6.2 (I dont update it because im having troubles rendering with Deadline with the latest Arnold)

My coworkers can see the crypto with Nuke, and I can see them with after effects

try downlaoding a previous version of Arnold, maybe the latest is buggy

[Stephen.Blair]

Works for me. But not if I create the Cryptomatte map myself. I had to let MAXtoA automatically create that Cryptomatte map.

[hyperviktor]

Is that with nuke 14 + latest maxToA ?

[Stephen.Blair]

Latest MAXtoA
Nuke 15, and I don't think the Nuke version matters. I can tell just by checking the EXR metadata before I even load it into Nuke.
I certainly couldn't get anything when I created the Cryptomatte map myself, which cost me at least an hour of investigation. 

[hyperviktor]

Did you solve it ?

[Stephen.Blair]

Yes, I had to let MAXtoA automatically create the Cryptomatte map.
So in Render Setup > AOVs > AOV Shaders > Maps, there has to be nothing. So that when I add the cryptomatte aovs and render, MAXtoA can add the map

[hyperviktor]

Yep, I've tried that way too, I let max add the crypto map, same result.

For some reason when I check the output metadata the crypto filtering is set to gaussian instead of cryptomatte and I have no clue how to change / fix it.

[Stephen.Blair]

Well, now I tried again with a new scene, and my manually-created Cryptomatte worked.

RE: not seeing the cryptomatte filter, that means the cryptomatte shader wasn't applied by MAXtoA. But all you should have to do (all that I did), was add a Cryptomatte map to the AOV Shaders in Render Setup.

I check it with oiiotool like this:

C:\ProgramData\Autodesk\ApplicationPlugins\MAXtoA_2025\bin\oiiotool -v --info "C:/Users/blairs/OneDrive - Autodesk/Documents/3ds Max 2025/renderoutput/AOVs.exr"
Reading C:/Users/blairs/OneDrive - Autodesk/Documents/3ds Max 2025/renderoutput/AOVs.exr
C:/Users/blairs/OneDrive - Autodesk/Documents/3ds Max 2025/renderoutput/AOVs.exr : 1280 x  720, 30 channel, float openexr
    channel list: crypto_material.R, crypto_material.G, crypto_material.B, crypto_material00.R, crypto_material00.G, crypto_material00.B, crypto_material00.A, crypto_material01.R, crypto_material01.G, crypto_material01.B, crypto_material01.A, crypto_material02.R, crypto_material02.G, crypto_material02.B, crypto_material02.A, crypto_object.R, crypto_object.G, crypto_object.B, crypto_object00.R, crypto_object00.G, crypto_object00.B, crypto_object00.A, crypto_object01.R, crypto_object01.G, crypto_object01.B, crypto_object01.A, crypto_object02.R, crypto_object02.G, crypto_object02.B, crypto_object02.A
    tile size: 64 x 64
    arnold/AA_adaptive_threshold: 0.015
    arnold/AA_samples: 3
    arnold/AA_samples_max: 3
    arnold/AA_seed: 951247345
    arnold/aovs/crypto_material/filter: "cryptomatte_filter"
    arnold/aovs/crypto_material/filter_width: 2
    arnold/aovs/crypto_material/source: "crypto_material"
    arnold/aovs/crypto_material00/filter: "cryptomatte_filter"
    arnold/aovs/crypto_material00/filter_width: 2
    arnold/aovs/crypto_material00/source: "crypto_material00"
    arnold/aovs/crypto_material01/filter: "cryptomatte_filter"
    arnold/aovs/crypto_material01/filter_width: 2
    arnold/aovs/crypto_material01/source: "crypto_material01"
    arnold/aovs/crypto_material02/filter: "cryptomatte_filter"
    arnold/aovs/crypto_material02/filter_width: 2
    arnold/aovs/crypto_material02/source: "crypto_material02"
    arnold/aovs/crypto_object/filter: "cryptomatte_filter"
    arnold/aovs/crypto_object/filter_width: 2
    arnold/aovs/crypto_object/source: "crypto_object"
    arnold/aovs/crypto_object00/filter: "cryptomatte_filter"
    arnold/aovs/crypto_object00/filter_width: 2
    arnold/aovs/crypto_object00/source: "crypto_object00"
    arnold/aovs/crypto_object01/filter: "cryptomatte_filter"
    arnold/aovs/crypto_object01/filter_width: 2
    arnold/aovs/crypto_object01/source: "crypto_object01"
    arnold/aovs/crypto_object02/filter: "cryptomatte_filter"
    arnold/aovs/crypto_object02/filter_width: 2
    arnold/aovs/crypto_object02/source: "crypto_object02"

.  

[hyperviktor]

Yes, I have tried both having max create it or adding it manually, it's visible there in the render setup yet doesn't do anything. Not sure what to do to fix it, never had an issue like this before.

[hyperviktor]

Would be great to learn if anyone else had a similar problem / how was it solved because at the moment, without crypto, we need to find ways to render crypto so it's breaking the workflow we have currently. I can't believe how something major like this can happen and no one knows about.

[Stephen.Blair]

Can you post an example scene that does not work? Since it's the cryptomatte setup, the scene doesn't need any real predocution assets in it.

[hyperviktor]

Sure, here it is. This is with max automatic crypto setup. In the metadata, crypto still uses gaussian filter, I get the same result when manually setting up crypto. Got this issue with the latest two arnold updates.

[hyperviktor]

No matter what I do, crypto filtering stays gaussian, it's driving me crazy !!!

[Stephen.Blair]

---

@hyperviktor wrote:

Sure, here it is. This is with max automatic crypto setup. In the metadata, crypto still uses gaussian filter, I get the same result when manually setting up crypto. Got this issue with the latest two arnold updates.

---

Yes, I can't get that scene to work. Clicking Render Setup > Render doesn't render the cryptomatte AOVs correctly. From the log, it looks like MAXtoA is stuck rendering the output file like it is rendering to the Arnold RenderView (that's why you see the gaussian filter).

If I batch render, then I get the good cryptomatte AOVs. Or if I export an ASS file and kick it.

[Stephen.Blair]

But then when I tried a second time, in a new 3ds Max session, batch render didn't work.

[Stephen.Blair]

A command-line render works every time, so far.

[wernienst]

Similar results here. I downloaded the provided test file, changed output folder and hit Render. I got 3 layers in Arnold RenderView: Beauty, crypto_object and crypto_material. The created exr file also has these 3 layers. Then I changed Color Management mode from Gamma Workflow to OCIO - 3ds max default. RenderView ok, but exr file has only black&white layers. Then I went back to Gamma Workflow, deleted all AOVs and created them manually - whatever I tried, I never got back the results of the first render (3ds Max 2025.3, MAXtoA 5.7.6.0).

And now the weird part. If I load these "broken" exr files in Photoshop (using the Exr-IO plugin) I got three colorful layers: RGBA (masked), crypto_material.RGB and crypto_object.RGB ! (Same results with Affinity Photo). So obviously the correct AOV layers exist somewhere in the exr file, but Max' image reader can't find them...

Btw, loading these exr files as texture map, the standard Bitmap map shows the b&w image, while Arnold's Image loads the Beauty layer correctly, and upon checking Single Channel, at least the channels of the other layers...

[hyperviktor]

Okay, so the problem is something that can be reproduced, how do I solve it ? I can see the same thing in my logs / metadata - arnold is sticking with the gaussian filter to render the crypto layers, no matter what I do or how I set up the crypto, even if I do separate EXR for the crypto, I get the same result, surely this is something to do with the latest maxToA plugin, I did not have this issue ever before.