Slow rendering - multiple frames

[RealViz]

Hello,
I'm trying FP 9.0.1 again, and I tried it on an older, larger scene. There's about 10xFP (grass, cars, bushes, trees...) and the first frame is rendered at standard FP8 speed. Each subsequent frame is slower. At about the third frame, even after 15min, Pass1 (V-ray) doesn't run out.
There is no animation of FP or other objects. Only camera animation (change of view).

[iToo]

Hi, perhaps this problem is related with the other post, because the bug would cause a mess in V-Ray.

With this bug fixed (in our internal build), i just rendered 100 frames from one of our tutorials, and everything seems correct. No delays, crashes or memory leaks.
Once we release next FP beta, please test it again. If problem continues, we'll investigate further.

Thanks,

[RealViz]

Thank you, I have the scene backuped in backburner and I'll try to resend it for a few rendernode.

[RealViz]

I tried the new beta 9.0.2 and unfortunately everything is the same. I'll try to find out what's causing it and post a simplified scene.
Edit:
it seems to be a memory problem. Each additional frame takes up significantly more memory than FP 8. But I'm looking further.

[RealViz]

Hello,
I'm sending a scene via wetransfer where the rendering slows down considerably on 3. frame of the animation. Even the computation of the LightCache itself is about 8x longer compared to FP8. I send the scene via backburner by default.
In two minutes of rendering there is only "pass 2" at FP9 and "pass 28" on FP8. However, it does not apply to the first frame, which is usually as fast as FP8.

Edit:
link deleted, contains paid models
link send via e-mail on helpdesk@itoo

[iToo]

Many thanks. We'll check it.

[iToo]

Thanks for the files. Unfortunately we're unable to reproduce the problem here.
We used FP 9.0.2, latest V-Ray 6, Max 2024 and 2025. We checked 3dsmax.exe memory as well, and it seems stable (about 15 Gb. RAM)

Please, try this:

- Open the test scene in your local workstation.
- Set a lower resolution and passes (so render test doesn't take forever).
- Open Windows Task manager->Details, to check memory used by 3dsmax.exe.
- Launch render, and check if problem is reproducible as using Backburner. Check memory consumption as well.

By the way, what V-Ray version do you use ?

[iToo]

One more thing: if problem occurs rendering locally, try setting this value in forestpack.ini (at C:\Users\<user name>\AppData\Local\Autodesk\3dsmax\<max version>\ENU\en-US\plugcfg):

samplesCacheLimit=0

It's necessary to restart 3DS Max to take effect.

If you want, you can change this in your Backburner node as well, to see if there is any difference.

[RealViz]

Hello,

changing samplesCacheLimit=0 solves the problem and everything runs fast. Both locally and via backburner.
What does this value mean? Won't it affect something else?

Thank you

[iToo]

Hi,

We added a new feature in FP9, to clean on each frame the cache used to store geometry.
This was necessary specifically for animated objects. If not memory grows until render ends.

Setting samplesCacheLimit=0 just disables it, working as FP8.

For some reason, this cleaning process is affecting the render process.
We'll try again to reproduce the problem here, to identify what is happening exactly.

[RealViz]

Thanks, I was looking forward to this feature as well. It's been my experience that animating with FP8 really takes a lot of RAM.
If I can find any more scenes where this appears, I'll send it over so you have more options to explore.

[RealViz]

Hello,
I tried restarting the problematic scene in backburner with FP 9.0.3 and everything seems OK even with samplesCacheLimit=10485760
Thank you
btw. what is the samplesCacheLimit unit? The number "10485760" stands for "b", "kb"? Or e.g. voxels within v-ray?

[iToo]

Hi,
This parameter is defined in bytes. So that's 10 GBytes of cache by default.