render time issues

[misi]

Rig:
CPU: AMD Ryzen 9 5950X 16-Core Processor 3.40 GHz
RAM: 64.0 GB
GPU 3080
Win 11, Nvidia driver latest update
Octane plugin: both C4D and Standalone (OctaneRender Studio+ 2024.1.2) is latest version
C4D: 2024.4.1

Hi All,

I got a scene with with the ABC animation file. One of them is from an xparticles vdb mesh and the other one is a thinking particle bake that controls a cloner.
It is an underwater scene in a swimming pool so a lot of refraction, reflection is happening.
The scene renders well in the first 50 frames, after that the render time jumped up from 13 minutes to 2h 40 minutes.
I tried to troubleshoot it and the following happens.
When I start the render from frame 50, the first frame renders well, but the 2nd jumps up. and whichever frame I start the render from the first frame renders correctly, but the second jumps up. I tried with multiple frame, 54, 58, 60. All give me the same result.

I am uploading the project here, should be ready in an hour or so if you would like to have a look.
https://www.dropbox.com/scl/fo/jzz7m67x ... cmx95&dl=0

Thank you for the help!

Mihaly

[misi]

I narrowed the issue down a bit.
It seems to me that it is related to the motion blur.
When I switch it off it renders well. I switch it back on, still renders well. I step one frame. The render time jumps up again.

[misi]

Something is not ok with the motion blur and cloner/particles.
The motion blur works with no issues until about frame 50-53 after that the render time jumps up with 15-20 times.

I start the render from frame 54, first frame ok, the next one is a total mess.
Then I start the render from frame 55, that is ok, the next one is not.

I found another post regarding a similar issue and @Aoktar suggested to push up the cpu threads under the octane camera tag, motion blur tab.
But it seems it is not working, or I am doing something wrong, as I tried to set it to 8, 12, 16, 24, but after I click away and go back to the tag, I find the cpu thread slider jumping to 0 every time.

[Toche]

Render times with XP and Motion Blur is a known issue, and sadly, it still hasn't been fixed.
viewtopic.php?f=85&t=84386#p437163