DoF going crazy in animations

[blinq]

Hi, I have problem with depth of field in animations. Everything seems to be fine but after rendering the whole sequence there are some frames out of focus. A sigle frame is completly blurred (or 2-4 frames per sequence). I can re render just that specific frames later and it will be ok. But the re rendering is annoying.
I'm working on 3ds Max 2023 and Vray 6 Hotfix 1 (but the issue was present on Max 2022 and previous Vray).
I'm rendering on GPU with Light Cache and a Vray Camera

[hermit.crab]

Could you simplify the scene and send it to us so we can investigate? A video reproduction would be great as well.

[hermit.crab]

I rendered the whole sequence as you've sent it, but the DOF seems fine on all frames. Does it happen on a particular frame (and only in animation)? Is it a random frame? Do you render locally? Could you share a few frames that illustrate the issue?

[blinq]

I forgot to mention that I render via Backburner. And I noticed that sometimes when the render resumes the first frame is wrong. Like when I turn off the render and it resumes from frame 87 that frame is incorrect.
I'm afraid I've re rednered all the corrupted frames. I'll upload an incorrect frame as soon as posiibble

[hermit.crab]

Tested it with Backburner, while stopping and resuming and everything seems to work as expected. Are there any errors printed in your Backburner log for these specific frames? Does it happen locally? Also, in which element is the exaggerated DOF present? RGB, Denoiser, or all of the elements?
Yes, please do include a sample corrupted image. If you can, try to reproduce the issue on a set frames (i.e it happens from frames 30-40) to speed up the debugging process.

[Ihno]

Im having the same problem it seems. I'll send the scene over.
All renderclients are @ the latest Vray version and current nvidia studio driver.
Im also using Backburner and it also seem to occure on the first frame a client picks up.

https://youtu.be/sa7PDZJ-TFA

My ticket number is: 202245

Edit: Thinking about it, its strange that it doesent happen on the first few frames. The bad ones that accumulate around f96-110 came out after I stopped the rendering yesterday.

[hermit.crab]

Im having the same problem it seems. I'll send the scene over.
All renderclients are @ the latest Vray version and current nvidia studio driver.
Im also using Backburner and it also seem to occure on the first frame a client picks up.

https://youtu.be/sa7PDZJ-TFA

My ticket number is: 202245

Edit: Thinking about it, its strange that it doesent happen on the first few frames. The bad ones that accumulate around f96-110 came out after I stopped the rendering yesterday.

Thanks for the provided scene. The issue seems to stem from the resumable rendering functionality and affects the resumed frame, however, on my end it seems it affects only the lighting, not DOF. We do have a similar issue logged in our system, however, I'll continue testing and write back with more info. Could you test if this happens locally?

[Ihno]

Yesterday I rerendered a few frames with resuable rendering turned off, and im pretty certain the issue still occurred in some of the frames.
But yes I can run a specific test for that.

[Ihno]

Yes, it definitely occurs with resumable rendering turned off.

[hermit.crab]

Yes, it definitely occurs with resumable rendering turned off.

I am still unable to reproduce the issue. No DOF flickering occurs with either resumable rendering active or not; when rendering locally or through Backburner. What kind of GPU do you have? Also, you didn't answer if the issue occurred when rendering locally (no backburner).

[Ihno]

I am still unable to reproduce the issue. No DOF flickering occurs with either resumable rendering active or not; when rendering locally or through Backburner. What kind of GPU do you have? Also, you didn't answer if the issue occurred when rendering locally (no backburner).

I'll run a test locally.

I got 5 computers working on this.
1x 1080
1x 4090
3x 2080 TI

I checked, the issue occurs on all those systems.

[Ihno]

It doesent happen locally.
I'll try and get you a log and some Exrs.