Rending Animation getting slow after ~470 of 510frames

#1

Hi,
I am currently rendering an 1920x1080 animation if a relatively simple part which I am rotating a few degrees to the left, then back, a few degrees to the right, back, a few degrees upwards and so on. Nothing is really changing significantly, no transparencies, but the rendering time per frame is increasing from around 2s to around 1.5-2.5min after having reached around 470 of 510frames.

The GPU is running at 96-100%, but the temperature is still at 66degrees C which schould be ok.

If I stop the render process and restart it will be super fast right from the beginning again.

Not sure if I am doing anything wrong!? Accoring to the task manager the memory usage of the GPU is almost at 100%. But why is that, shouldnt it start over at each frame?
If somebody is having a hint, it would be great.

Thanks in advance

Screenshot%202025-01-31%20123245
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#2

If possible I should open a support ticket and share the scene.

I encountered the same sometimes as well but I do a lot while rendering so I always think that’s causing it.

And I always render to stills and never video so I use your workaround by just starting the render again at the last frame.

If you open a ticket I would include your KS version and Nvidia driver version.

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#3

Thanks Oscar,
I was thinking about the same when I experienced the slow down the first time.During rendering I was doing some CAD work and had a Youtube Video running on the second monitor. It didn’t help when I closed all other applications. I even rebooted and closed for example the space Mouse driver, all cloud services and so on.

So probably it is a bug. I will open a ticket as you recommended.

By the way: I am rendering to stills too, which are saved separately and merged at the end to a videofile. Thats why I think that is strange it is making a huge difference in render times per frame.

I checked a few of the frames and compared the render times. On a few frames I checked the resulting render is 100% comparable, you can not see any difference. It is just the render time which is 4second in the beginning and 5min04sec more towards the end of the animation.

I am on Keyshot Studio Pro 2024.3 (13.2.1 Build 1 14.12.1) on a HP ZBook Fury G10 with 64GB RAM, 13th Gen Intel® Core™ i9-13950HX 2.20 GHz, NVIDIA RTX 5000Ada Mobile graphics and Windows11 24H2 build 26100.3037.

#4

HI @stephan.esser,

Just realised (must be my age) I had the issue some time ago as well with the 2025.1 Beta, I actually posted it here: 2025.1 Beta | GPU Render in background - For Beta Testers - Luminaries

As you see my frame times went also up suddenly but I was actually on a newer Nvidia driver than 565.90 and didn’t had the issue after reverting to the Studio drivers of past September.

Yesterday Nvidia released a new driver and I always like to check what’s fixed and did see this:

[KeyShot2024] TDR on loading the scene Camera Keyframe Animation [4909719]

Just sounds a bit cryptic and not sure if that’s indeed the bug that made the rendertime suddenly longer. Do you know @philip.rasmussen?

Another thing, I was using Background Rendering and I’m not sure if that’s also a trigger for it to happen. Most of the time I have background render unselected since I don’t really notice a difference between those anyway using GPU. I can always do things in the meantime.

I normally don’t like to be on older drivers since there’s also software that runs better on new drivers, but you could try it. What I always do when I install the Nvidia driver is ‘custom’ installation and disable GeForce Experience and select ‘clean install’. I also deselect the audio drivers since I don’t want my monitors to make any noise.

Gutes Wochenende!

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#5

Hi,
I have been busy on some other things and forgot to reply with what I found in the meantime: There was a planar light in the original scene which I took of from a collegue who did a still rendering of the same product. It seems that one was causing the slow down after the mentioned 470 frames of the animation. When I turned of that planar light it went renedered all to the end without slowing down.

Anyhow I will first transmitt that message to the Keyshot support now. So they can check although it is solved for me at the moment. I am happy that in this case the planar light was not really that important for the use of that animation.

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