V-Ray 3.60.01 - Very Slow Render Speeds

V-Ray V-Ray for SketchUp Issues
1

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?

2

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

3

"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

4

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

5

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

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

6

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

7

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.