The Achilles heel of V-Ray - the quality slider as a pitfall


I never used the quality slider before and after some tests I’m surprised - it complete fails to get quality. VfR Next works wonderful, but not with this settings. Maybe I’m totally wrong, but I get a lot of noise at the highest quality.
For example the highest quality settings: the noise threshold is pushed very low, but max subdivs 24 are not enough to reach this tight limit - the sample rate pass shows the disaster, the noise threshold is not reached at nearly the complete image. The min subdivs 2 and the LC raytrace 6 try to push the quality, but this doesn’t help.

I don’t understand who setup this slider and why this settings, but I would recommend to use min/max subdivs 1/100 and use the noise threshold for adjusting the quality only. Most 0.02 is quite good, 0.01 is high quality and 0.005 is more than enough. Quick renders can be done at 0.05 … 0.03, the denoiser can help to get this quick and noisy levels quite clean too.

Here the sample rate pass - at the most areas the noise threshold is reached, only at a few little areas more samples would be needed. The sample rate pass looks quite good.

Some words to the LC options. I use sample size 0.01 and Raytrace 1 all days. I found that a bigger sample size can cause a strong slow down. Unfortunately per default it is set at 0.03. So, be careful. I have seen a 400% speed turbo by jumping to 0.01.
Raytrace 1 helps to avoid light leaks, if problems should appear, a higher value could help. For high res interiors I like to use a high subdiv count at 2000 … 3000 to get a good basic GI solution for the further calculation.
The LC is a quick pass most, so this option doesn’t need so much attention. If someone like to render animations and every second counts, than for exterior shots low subdiv values are good to use like 500.

I’m using the GPU mode only and have not experience how to use the CPU mode at VfR Next. Some quick test shows me that the quality slider dosn’t work well here too, the sample rate pass is red only.

If someone has some more ideas for the basic setup of VfR than I would be glad about some posts here.

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