Rendering an environment with lots of vegetation gets stuck after a few frames

[nicolas_chan]

Hi, I'm working on a collab project and I'm running into a weird issue while rendering an environment with lots of foliage, trees, etc. What happens is that a few buckets, usually 2-4, get stuck and can't be resolved. The problem usually occurs after 2-10 frames or 1-3 hours of rendering without following any obvious patterns.

I tested a lot of different things like disabling objects, changing render settings, new camera, or exporting everything into a new hip file, etc., but nothing seems to work. I uploaded a stripped down version of my scene here just in case:

https://drive.google.com/file/d/1s59...ew?usp=sharing

Thank you in advance!

[tsvetomira.girginova]

Dear nicolas_chan, hello.

I am looking at your scene. It is a heavy one, yes, even the stripped version.
It crashed at the very beginning while trying to load some assets, but now it is rendering fine, but slowly.

Could you please add to your houdini.env file :

HOUDINI_DSO_ERROR=2
HOUDINI_TEXT_CONSOLE=1

and check are there any errors shown.

It is awaited that you are using a powerful configuration, but we will appreciate if you share your system specs to test the scene on a similar setup.
It was previously detected that in some cases Buckets may look frozen, but the rendering is ongoing.
I will pay more attention on the processes and share what was noticed.

Best regards,
TS

[nicolas_chan]

Hi, thank you for the response! I've run a render with the modified env variable, but no error is shown. I also noticed that the buckets don't get stuck, but rather take forever to render, similar to what you said, though I'm not sure that they ever finish.

The bucket splitting also won't work as soon as the first bucket gets stuck (in some cases, it already split one bucket into fourths and then got stuck and didn't continue splitting).

We tested the scene on two different machines just to be sure the error wasn't caused by my machine, and I also tried different versions of Houdini 19.5 and different versions of Vray from a 6.0 (I'm not super sure which version it was exactly) to 6.10.09.

First Machine; Ryzen 9 7950x
DDR5 128gb (4x32) RAM
RTX 3090 24GB

Second Machine:
AMD Ryzen 7 3700X
DDR4 128GB RAM
RTX 3060 12GB

Best regards!

[tsvetomira.girginova]

Hello again.

Excuse us for the extremely delayed response!
Yes, the scene is a complex one.

I have tested in a smaller frame range and with decreased resolution.
But the thing that changed the render time and no crashes were experienced was restoring Camera > Sampling > F-Stop to its default value (5.6).

During the process was also noticed a known issue when V-Ray Proxies are stored on a network location. The logging is improved through VMAX-8986.
If you enable Text Console as advised in my previous post (via the env vars), you will be able to see when some Instance object is not found within the rendering process.
At the certain moment you could try restoring F-Stop value to default and if possible save the V-Ray Proxies locally to confirm on your side will the process be improved.

I will be out of office for the next few weeks, but my colleagues will follow the thread.

Excuse me once more for the delay!

Best regards,
TS