Arnold - No Qt platform plugin could be initialized

[ruchit-bhatt]

Version: Gaffer 0.60.7.0-winx64
Third-party tools: Arnold-6.2.0.1

Description

Gaffer returns below error on accessing any Arnold node.

[ericmehl]

Hi @ruchit-bhatt,
A few questions for you to try and sort this out:

Are you by any chance running Gaffer from something other than a regular, local Windows session? Something like a remote desktop or VNC environment?

What video card are you using?

Do other Gaffer nodes work? Try the Checkerboard image node and see if you get any errors.

Are all Arnold nodes affected, even ones like PointLight and ArnoldAttributes? Or is it only viewing Arnold shaders that cause the error?

[ruchit-bhatt]

GPU: Nvidia GeForce RTX 3060
Remote Desktop: NoMachine, HP-RGS

Do other Gaffer nodes work?

Yes; Checkerboard, PointLight, ArnoldAttributes are not giving any errors

[ericmehl]

I couldn't recreate the error here, including trying NoMachine. Have you tried using the built-in Remote Desktop? It may be because I'm using a Quadro card though.

I know certain things including OpenGL were not able to run in some remote sessions on GeForce cards, but I think that restriction may have been removed.

I found this post : https://www.khronos.org/news/permalink/nvidia-provides-opengl-accelerated-remote-desktop-for-geforce-5e88fc2035e342.98417181#:~:text=NVIDIA%20has%20created%20a%20special,your%20OpenGL%20application%20will%20run. that makes it sound like it may be possible with (maybe) a driver update and running the NVidia OpenGL compatibility program.

Give that a try and see if it solves it.

[murraystevenson]

I was helping someone get up and running with Gaffer & Arnold on Windows and we ran into a similar issue. Following the below steps from the Autodesk knowledge base to copy qwindows.dll from one folder to another seems to fix it. The article suggests "a conflict with 3rd party applications using QT libraries" could be causing it, but that workaround appears to at least work for now...

https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/This-application-failed-to-start-because-it-could-not-find-or-load-the-Qt-platform-plugin-dialogue-appears-when-running-a-Nastran-analysis.html

[ericmehl]

Thanks a lot @murraystevenson, that is very helpful. So you copied and pasted only within the AdskLicensingAgent directory? Or did you copy qwindows.dll to a Gaffer related directory?

Either way it suggests Arnold may need QT to check on licensing, which I hope is not actually the case.

[yutapple]

@ericmehl It was me who @murraystevenson helped and all I did was copy that qwindows.dll from "\AdskLicensingAgent\platforms" to "\AdskLicensingAgent" and the error went away.

Also big thank to you for making this windows version! It is AMAZING!!

[ericmehl]

I randomly came across this solution to what sounds like a very similar problem with Houdini :
https://arnoldsupport.com/2022/09/20/the-case-of-the-hrender-that-failed-to-start-adsklicensingagent/

The recommendation is to point QT_QPA_PLATFORM_PLUGIN_PATH to the Autodesk licensing directory before running Gaffer / Houdini. That might be easier in some cases where you don't have permissions or just don't want to delete the Autodesk file.

Something like this :

set QT_QPA_PLATFORM_PLUGIN_PATH=C:\Program Files (x86)\Common Files\Autodesk Shared\AdskLicensing\Current\AdskLicensingAgent\platforms