V-Ray 3.60.01 - Very Slow Render Speeds

[particlerealities]

I just updated my V-Ray to the latest version yesterday afternoon. I opened a scene I started modeling on Monday of this week, clicked 'render' and the default HDRI that came in automatically with the Dome light on Monday was missing today. Once I fixed that (deleted the dome & inserted a new one), I noticed my render times are essentially 3x longer than they were prior to the update. Is anyone else experiencing longer render times with the new version?

[konstantin_chaos]

I just updated my V-Ray to the latest version yesterday afternoon. I opened a scene I started modeling on Monday of this week, clicked 'render' and the default HDRI that came in automatically with the Dome light on Monday was missing today. Once I fixed that (deleted the dome & inserted a new one), I noticed my render times are essentially 3x longer than they were prior to the update. Is anyone else experiencing longer render times with the new version?

Hi particlerealities,

Do you have 'Subpixel Clamp' enabled?

Also, if you can share a scene that renders slower we'll be able to investigate the issue further.

Regards,
Konstantin

[particlerealities]

"Subpixel Clamp' was not enabled. My history panel does not have many views saved, but prior to the update, "Scene 12" rendered in about 58 seconds @ 1280x720 with a Noise Threshold of 0.1 and denoiser and ambient occlusion enabled. This morning, I reset the render settings to default, set the Noise Threshold to 0.1 and enabled Ambient Occlusion and clicked render @ 1280x720. It rendered in 3m 1.0s with a noise threshold of 0.1 (it was only a few seconds slower with Ambient Occlusion disabled). The only thing that changed in my model after the V-Ray update was the addition of the Edges map to the "Bump/Normal Mapping" slot of two materials. Disabling those slider switches had no effect on render times.

Here's a link to the file:
https://app.box.com/s/e7ghu9pt19m1jknl6wjt6hr3fp9oac82

-Eric

[konstantin_chaos]

Here's a link to the file:
https://app.box.com/s/e7ghu9pt19m1jknl6wjt6hr3fp9oac82

Hi Eric,

I downloaded the file but it looks like it was saved with V-Ray 3.6 making it hard for me to do 3.4 comparison.
Can you please share the original (saved with 3.4) file?

Thanks in advance,
Konstantin

[particlerealities]

Give this file a try. This was restored from a server backup prior to my V-Ray upgrade.

https://app.box.com/s/m4r19esk5ilxj5kbmb64riexntkj1hnn

[konstantin_chaos]

Give this file a try. This was restored from a server backup prior to my V-Ray upgrade.
https://app.box.com/s/m4r19esk5ilxj5kbmb64riexntkj1hnn

Hi particlerealities,

Thanks for the test scene.
On my system the your scene renders with the same speed in 3.4 and 3.6.

On the other hand there is a Denoiser render element enabled and a denoiser pass calculated after the image has been rendered.
And what I've noticed is that sometimes in V-Ray 3.6 the Denoiser doesn't recognize your GPU and calculates on the CPU instead.
This additional time is added to the render time and might possibly cause a difference.

Can you try the following:
> Open 'Extensions/V-Ray/Tools/GPU Device Selection' and let me know if you see your GPU listed there?
If not, this might be causing the issue. I was experiencing that at one point.

Regards,
Konstantin

[particlerealities]

Hi Konstantin - I see all 3 of my GPUs listed, with 2 of them enabled, including C++/CPU. I'm going to switch to GPU rendering on this one. It's immeasurably faster than CPU on this scene. I don't want to waste any more of your time on this one.