3.3 twice as slow as 3.2

[munderwood]

I was just testing some of the differences between V-Ray RT GPU 3.3 and 3.2 and noticed a large speed decrease between the two. I was using the scene at the link below. 3.2 was installed on max 2014 and 3.3 was installed on max 2016. RT CPU also seemed to about 50% slower in the newer version. I'm just using the default settings which you switch RT GPU to Cuda, and I'm running a Titan X. The GI between the versions seems quite a bit different, 3.3 renders out with brighter GI. Anyone have any ideas?

http://www.cggallery.com/files/vray_optimization.zip

[vlado]

Thanks for the scene, will take a look at what's going on; there are quite a few changes in the RT engine, it's possible that we missed something.

Best regards,
Vlado

[glorybound]

When I first updated to 3.3, it was mid-stream on a project, and it was much slower. On new project, with the update, things were much faster.

[yavor.rubenov]

Hello,

When you open the scene in V-Ray 3.3 do you choose "Yes" or "No" to the warning that pops up ? As you are experiencing brighter GI I assume you clicked "yes" - this changes some of the rendering settings like:
- new image sampler - the new image sampler treats noise in a different way and you can't compare renders without changing the noise threshold
- enabled reflective GI caustics - this leads to brighter GI but takes more time to calculate
- Dynamic noise threshold for the progressive sampler (this affects RT CPU and RT GPU too) - leads to more even noise distribution.
- Internal spectral color space switched from CIE RGB to sRGB;

All those changes lead to cleaner more correct image but they do take time. Rendering this scene in 3.3 produces much cleaner image.

If you want to switch to the old behavior with 3.3 - look here http://forums.chaosgroup.com/showthr...avior-switcher

Also you could look in this topic http://forums.chaosgroup.com/showthr...image-with-SP3 for some more info on using the new image sampler.

Best regards,
Yavor

[munderwood]

The reflective GI caustics was the the main issue, unchecking that gives me an image that looks the same, and indeed does have better sampling with a slightly higher render time. This scene was saved using V-Ray Advanced as the production renderer. When I open the scene I can say no at the pop-up it keeps the old settings, but when I switch to RT it doesn't give me the pop-up and automatically switches to the new settings. This isn't a big deal if you know that is happening, but with the current behavior I couldn't tell it was being switched. I think it should still retain the old sampling settings when you switch to RT if you had them that way in Adv., or atleast give me another pop-up. Thanks!