Arnold aiSetParameter nodes from mtoa 3.2.2 don't seem to be backward compatible with 3.1.2.1

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V V asked · Aug 05, 2019 at 06:45 PM

Arnold aiSetParameter nodes from mtoa 3.2.2 don't seem to be backward compatible with 3.1.2.1

Hi,

We're making heavy use of aiSetParameter nodes in our look dev and lighting pipeline - we basically use them to assign materials, smooth geometries, apply displacement, etc.. etc.

While working on a very big maya scene with many assets and aiSetParameter nodes we noticed that the scene was very very slow to render, even though it was not so complex.. I mean we've done way more than that. :)

We currently use mtoa 3.1.2.1, and we decided to check the release notes of version 3.2.1.1 which, among the other things, say:

Fixed slowdown with many operators

So we downloaded the new version in order to test if the slowdowns were fixed (we tried both 3.2.2 and 3.2.1.1 to be honest).

But we discovered that some aiSetParameter nodes (created with the 3.1.2.1) are not working anymore with 3.2.2 - they give the classic pinkish color at render time, as if they were not evaluating correctly. Of course all of the nodes were working exactly fine in the previous version.

We also noticed that in this version (3.2.2) we have to check Export all shading groups in the arnold render settings in order to make the aiSetParameter work.

Now, if we create new aiSetParameter nodes and use them to assign shaders they work just fine, so it appears that it's just that the old ones for some reason are not compatible with this arnold version.

Can you confirm it? We've got quite a few assets already done with the old version, it seems odd that we should republish them just because of this regression between minor versions.

Thanks!

Maya version is 2018.6, OS is Centos 7.6.

Steps to reproduce the issue

Create an aiSetParameter node in version 3.1.2.1, upgrade mtoa to 3.2.2 and check that it works.

arnold mtoa nodes operator

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Answer 1 · 2019-08-05T18:46:48Z

Stephen Blair answered · Aug 05, 2019 at 06:46 PM

Something broke the automatic export of referenced shaders, I can repro in the current MtoA too.

You'll have to use Export All Shading Groups for the moment...

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V V · Aug 05, 2019 at 07:01 PM

Thanks Stephen! But Export All Shading Groups doesn't work for all nodes - some aiSetParameter nodes are not assigning the shader properly even when this checkbox is ticked. Also, by referenced do you mean a Maya reference? Because during our lookdev we don't have any referenced shader (only during lighting).

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Stephen Blair ♦♦ V V · Aug 05, 2019 at 07:19 PM

By referenced, I mean that an assignment statement references a shader node.

For example: *shader = "aiUtility1"*

MtoA is supposed to automatically export the referenced shader.

What kind of set parameter nodes do not work with shaders? Do you have a simple scene that shows the problem?

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V V Stephen Blair ♦♦ · Aug 05, 2019 at 07:41 PM

Got it. So yes we are doing many assignments like that since we basically assign shaders to geos in this way. The ones that don't work are also just simple aiSetParameters like the one you showed. I can try to reproduce the error by creating a scene with 3.1.2.1 and then move to 3.2.2 and see if the issue remains. Otherwise I can send you the maya scenes which are giving us errors. Basically the same scene works under 3.1.2.1 but renders completely pink with 3.2.2 (even w/ the Export all Shading Groups check)

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Answer 2 · 2019-08-05T21:35:51Z

V V answered · Aug 05, 2019 at 09:35 PM

Ok I did a test (create operators with 3.1.2.1, test them on 3.2.2) with a very simple scene and it worked. But then I opened of our assets using 3.2.2 and it was completely pink, while in 3.1.2.1 it was rendering just fine. Exported an .ass and while it contains the set_parameter and the merge nodes, it doesn't contain any shader.

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Stephen Blair ♦♦ · Aug 05, 2019 at 09:43 PM

If you can send something to support, we can take a look.

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V V Stephen Blair ♦♦ · Aug 05, 2019 at 09:51 PM

Thanks, Stephen! I'll send the Maya scene to the support email.

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Answer 3 · 2019-08-06T10:32:50Z

Ashley Handscomb Retallack answered · Aug 06, 2019 at 10:32 AM

It looks like a bug in the shader detection if you remove the spaces between the parameter '=' and value it should work.

so

"shader = 'myshader'

should be

shader='myshader'

I will make a bug report for the spaces issue

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V V · Aug 12, 2019 at 03:03 PM

Thanks Ashley, without spaces it works. Very very weird regression bug! Did you open an issue? When can I track it?

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Stephen Blair ♦♦ V V · Aug 12, 2019 at 08:53 PM

It's MtoA ticket #3939, should be fixed in the next bugfix update.

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