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Rendering with Arnold in Houdini and Solaris using the HtoA plug-in.
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Arnold constantly freezing on "Updating Nodes"

Message 1 of 7
306 Views, 6 Replies

Arnold constantly freezing on "Updating Nodes"



I've noticed that Arnold keep freezing on "Updating Node" on both CPU and GPU.

Usually it will sit forever at this point and any while the Houdini scene remains functional, any attempt to interrupt the render will cause Houdini to freeze and require and "End Task".


Example below, the scene should cache (Restart Arnold or new render) within 5 seconds, however left for over 10mins nothing happens.


Trying to restart render, switch back to OpenGL, etc. will cause Houdini to freeze.



Attempt at interrupt:




all the best,



Houdini Core Version 20.0.590
Arnold Core:


CPU: AMD Ryzen TR 3990x

RAM: 128GB
OS: Windows



Message 2 of 7
in reply to: am_wilkins

Hi Andrew


I had a similar report from another user, and I've been trying to repro. But no luck with that so far.

I'm not sure what's in the scene that requires that much "updating nodes"
Maybe you could send a log from another render that gives me an idea? DM it if you prefer, or use the support channel:

// Stephen Blair
// Arnold Renderer Support
Message 3 of 7
in reply to: Stephen.Blair

I can try to provide more information. Proper logs are still not always successful for me, especially though Husk.

The scene itself is actually quite small and basic, those nodes are likely some geo based grass instanced to points.



Message 4 of 7
in reply to: am_wilkins

On Windows, if you set HOUDINI_TEXT_CONSOLE=1, you should get all the Arnold log in a command prompt window. I have this in my package file:


                    "value": "1",
                    "method": "append"


// Stephen Blair
// Arnold Renderer Support
Message 5 of 7
in reply to: Stephen.Blair

Thanks, I'll have to try this out cause not seeing logs is frustrating.




ps. in initial testing Redshift automatically always saves a log out to a file, which is cool to see.

Maybe some functionality like that will help you get logs from users in the future.

Message 6 of 7
in reply to: am_wilkins



I caught a scene that was doing this, however the logs don't seem very useful:

03:26:32 12338MB         |  OIDN Device Enum, Device 0 : NVIDIA RTX A4000
03:26:32 12339MB         |  OIDN Device Enum, Device 1 : AMD Ryzen Threadripper 3990X 64-Core Processor 
03:26:32 12341MB         |  default OIDN device created
03:26:32 12343MB         |  Selected OIDN Device Type: CUDA
03:26:33 12678MB         |  creating root object list ...
03:26:33 12678MB         |  the following procedurals were initialized serially:
03:26:33 12678MB         |     instancer (27 instances)
03:26:33 12678MB         | node initialization done in 0:07.44 (multithreaded)
03:26:33 12678MB         | updating 305710 nodes


It was rendering fine, I stopped the render, made some adjustments and started it again. Then it just sits on " Updating all 305710 nodes" indefinitely until I'm force to try cancel the render. In which case Houdini freezes.

Message 7 of 7
in reply to: am_wilkins

Here are 1 million PigHeads instanced on a grid.

In houdini-19.5.752 with htoa-

Smooth updates in the IPR when orbiting and panning the camera.


Here is the exact same USD file in houdini-20.0.590 with htoa-

The time to first pixel is about the same, but the rendering speed is slower, and there's a significant lag when orbiting the camera, and an even greater lag when panning the camera. 

This is consistant in all scenes. 


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