cryptomatte AOV not quite working

[Anonymous]

Newbie learning maya (from 3ds max)

I am trying to get crytomatte passes out of Arnold.

When I look at the CM layers in the arnold renderview they look good. I then export the frame as a multi-pass exr.

I then bring them into compositing (in this case after effects using ProEXR).

After Effects also sees the layers fine, but there isn't any actual cryptomatte data to create mattes from.

In other words, so the passes look visually correct, there are no ID's (material or object or asset) to create mattes with.

I feel like I am probably missing one simple step, but that I am close!

[jordan.giboney]

Hi @Anonymous 

Thanks for posting! 🙂 Are you following a tutorial or process? This Solid Angle link has a great test scene that you can use to compare/contrast with what you already have: Crypotmatte AOV User Data

Also, have you installed the appropriate plug-ins and updates for Adobe? Full disclosure I am just learning about this, but this post has a link at the bottom of the article to the update/download.

Thanks for your patience with this! I look forward to hearing from you.

PS, more cool cryptomatte stuff (but in nuke)

[Anonymous]

---

@jordan.giboney wrote:

Hi @Anonymous 

Thanks for posting! 🙂 Are you following a tutorial or process? This Solid Angle link has a great test scene that you can use to compare/contrast with what you already have: Crypotmatte AOV User Data

Also, have you installed the appropriate plug-ins and updates for Adobe? Full disclosure I am just learning about this, but this post has a link at the bottom of the article to the update/download.

Thanks for your patience with this! I look forward to hearing from you.

PS, more cool cryptomatte stuff (but in nuke)

---

It's weird but when I would import a single frame created by the Arnold Renderview window (via "save as multilayer exr"), I would have the issue that I outlined above. But when I rendered the sequence and imported it all was fine, the crypto's worked as designed.

Thanks.

[jordan.giboney]

Hi @Anonymous 

Thanks for reply! That is strange. Can you tell me what exact version of Maya and Arnold you are working with?

For Maya, select Help > About Maya (it will list the Cut ID and exact version + update installed)

For Arnold specifically, make sure you are in the rendering menu, and then select Arnold > About (a new window with the exact version will open)

Arnold updates are published at a different rate than Maya, and chances are that the version included in your initial Maya download is not the most current one 🙂 To install the latest one, check out the Solid Angle downloads page: https://www.arnoldrenderer.com/arnold/download/ (The current version of Arnold for Maya is MtoA3.2.1)

Thanks again for being a part of our community!

[jordan.giboney]

Hi @Anonymous 

Hope you had a good weekend 🙂 Just wanted to check in and see if you had a chance to see what versions of Maya and Arnold are installed on your machine. Any new developments with this topic?

Thanks again for being a part of our community! 

[Anonymous]

---

@jordan.giboney wrote:

Hi @Anonymous 

Hope you had a good weekend 🙂 Just wanted to check in and see if you had a chance to see what versions of Maya and Arnold are installed on your machine. Any new developments with this topic?

Thanks again for being a part of our community! 

---

Here is what I have found -

It seems that checking "merge AOV's" caused a lot of the havoc I was having. Once I spit out separate AOVs  things worked more or less as expected.

This should be all up to date version wise as both Maya and Arnold were installed last month.

Thanks

[jordan.giboney]

Hi @Anonymous 

Thanks for the reply! Happy to hear that unchecking "merge AOVs" resolved the behavior. Any new issues we can tackle?

As a FYI, updates are not included in the initial download of Maya/Arnold. This means that regardless of when the program was downloaded, updates will need to be applied manually from the website or desktop app.

Thanks again for being a part of our community!

[jordan.giboney · Accepted solution]

Hi again @Anonymous 

I reached out to our contact at Solid Angle, and it turns out that this is a limitation with the Arnold Render View - it doesn't include the necessary metadata for multi-channel EXRs to work as expected. The renders will have to be outputted through the Batch render process to be successful.

This is expected as the Arnold render view is saving just the pixel output from Arnold, not the metadata. However, if you would like to vote for this to change in a future version of Arnold/Maya, I would recommend posting on our Maya Idea Station where you and other Maya users can vote for ideas to get implemented into a future version.

Thanks again for being a part of our community! 

[jordan.giboney]

Hi @Anonymous 

I hope you are doing well 🙂 I wanted to check in and see if you had a chance to review my previous post, and if there were any follow up questions.

If the information is sufficient and you are good to go, it would be awesome if you could hit that solution button so that others with this same problem can find the answer faster. 

Thanks again for being a part of our community!

[stevenjamestaylor]

@jordan.giboney  can you clarify something- if Cryptomatte AOV's only work in batch render does that mean they will not work in Render Sequence as well? is there a comprehensive list of things that are similar- e.g. work in Batch render  only.

thanks

[Stephen.Blair]

You have to render it. Batch or sequence or render current frame or export ass and kick.

Saving an EXR from the Arnold Render View won't give you EXRs that you can use with cryptomatte (the required metadata won't be there).

[mspeer]

Hi!

@Anonymous and @stevenjamestaylor .

The rendering is not the problem, but the save process from Render View (Maya and Arnold) is different from directly rendering/writing to disk.

Using Render Sequence, for rendering just one frame should work.

[snake3y3s]

Has this been corrected/updated in the latest Arnold?

[Anonymous]

No, it's still not working when saving from render view

[bjones9JMJJ3]

Gah, this is a garbage limitation! 

I would have assumed Arnold is Arnold is Arnold... yet another crappy Maya behavior to add to the list of crappy Maya behaviors...

[snake3y3s]

well, its unfortunately due to the fact that when saving directly from the Arnold render view, it does not write the metadata into the file.

Its just taking whats in the frame buffer and writing that

[bjones9JMJJ3]

Yes, a garbage limitation. It's Autodesk once again phoning another acquistion in and doing nothing to unify it with their existing software, or make the functionality user-friendly and unified. It's lazy software development, plain and simple.