OTOY Forums

Hi,

My renders are flickering (caustic luminance) inconsistently when I have alembic of fish in the scene. when I hide fish from render, the caustics renders correctly. I created alembics from rigged fish swimming in a loop (in c4d). I placed them in the scene as instances or inside cloners. motion blur is a bit glitchy (I set octane tag motion blur to transform/vector which works but first few frames it sometimes skips blur.). My scene is rendering a Caustics pass for compositing so there is an ocean floor showing the caustics from the ocean surface. It also casts caustics onto the fish but you can see from screenshots it dims randomly during Live viewer it looks correct until a certain amount of samples then it goes dark for some reason. If I remove alembic fish (3 types) the caustics on the ocean floor renders consistently. Something weird going on with alembic + Photon Tracer + caustics.

Screenshot:
Sample_01 - scene is looking correct at 432 samples.
Sample_02 - at 663 you start to see the right side rendering darker.
Sample_03 - complete render at 1024 sample, the caustics is darker then it should. When I render animation , the darkeness is not consistent and its different. Sometimes I get correct frames but never all of them.

--------- Requested Info-------------
OS: Windows 10
GPUS: 2x RTX3090 (master) + 3x RTX3090 1x RTX3090ti 2x RTX2080ti (slave)
RAM: 64GB (master) / 128GB (slave)
Driver: Game Driver: 531.79 (also tried latest Studio driver (531.61) but same issue)
Octane Standalone version: N/A
Octane Plugin version: 2022.1.1
Host App: Cinema 4D R2023.2.1 (build 2023.CL401745.844493561)
Octane Log window / Console window output: N/A

Hi,
could you share a complete screenshot from kernel panel?
What about the fish and sand/floor materials?

ciao,
Beppe

Low are the probabilities that the issue being caused by the Alembic on itself, although perhaps related to it somehow. More details or sharing the scene with the OTOY team would help investigate that angle.

Regarding Photon Tracing, could this page help? I've shared some details and tips. As Beppe mentioned, sharing the whole Octane Kernel tab settings is recommended.

Thanks for the quick replies...

I am currently under a deadline so I figured out a workaround - render the floor without fish and render the fish separately (the fish (alembic) pass still flickers but its subtle enough not to get as noticed as a floor dimming). I will reach out again soon and post a project file. I appreciate you looking into it.

Materials - I tried without materials and it still dims.

I've attached my kernel screenshot for now.

Another problem I encountered (could be related) but I have a whale animation (also alembic) and it does not update the animation each frame. I have to re-render each frame that it stalls... super annoying..

Next week sometime I will have more time - Thank You guys very much!

Ok I had some time while rendering.

As for materials, nothing special - the ocean surface uses a default specular material (with 0.00001 roughness) Ground is basic diffuse material with alpha.
Regardless of material, if it works on one frame, it theoretically should work on all frames, but for some reason it's flickering on randomn frames.

If this helps, here is a link to the project file:
https://www.dropbox.com/s/i0o2bsgyrbz60 ... E.zip?dl=1

This scene does not have the whale, but same issue with floor caustics flickering with Alembic Fish. If I turn off Fish, the floor renders fine.

You may have to set samples down (128 or 256) but over time you will see in picture viewer the luminance gets lower on some frames randomly. Then turn off parent STAGE>GEO>BG FISH and rerender - the floor will not flicker anymore.

Thank you very much for looking into it.



Render range is set to 20-90 - just need to adjust # of samples (currently set to 2048) then render to pictureviewer.

Thanks again,
M

Hi again,

I've created 2 videos for you:

Rendering - shows the random flickering when rendering the scene twice. i.e F27 was black the first time, then normal the second time.
https://www.dropbox.com/s/26ga0bi1vkc6c ... r.mp4?dl=1

Scene Overview - I go through how the scene is set up and shows the material attributes.
https://www.dropbox.com/s/4c8ayowpda2kn ... w.mp4?dl=1

Thank you again for the support.

M