Understanding the min shading rate

[circus studio]

Hello,

I have two questions about the "min shading rate" knob.

1. On the doc, I see that is more for the progressif sampler but in one post on the forum, I understand that is important for the bucket sampler too.

If I understand well, It's a "floor rate" for VRay in order to take the good decision in the adaptatif sampling.

But I just want to know if the default value of 6 says that all shading will be sampled with this minimum (6 subdivisions dispatched for all channels, SSS + spec + refract, etc.) or if it says that each component takes 6 subdivisions each (6 for SSS, 6 for spec etc).

2. And normaly for these 6 subdivs, it is 6 subdivs in the DMC sampler? If yes, why this knob is not in the DMC tab?

Thank you by advance,

Best regards

Edouard

[dgruwier]

I don't think I know the details of how it works well enough to help you with your specific questions, but I will mention that with recent versions of vray, sampling is optimized to the point where tweaking the min shading in either direction is more likely to be detrimental than not. Vlado actively discourages people from using it, and it's likely to be hidden from the interface in the future.

[circus studio]

Thank you for your answer.
I use Next 4.12 for the moment. Do you refer to more recent release in your answer?

Best regards

[yolov]

4.12 should have everything needed. If you keep 'use local subdivs' off (which is the default), the min shade rate at 6 (default), all you need to tweak is the image sampler subdivs and noise threshold and nothing more. V-Ray will take care of all the rest.