V-Ray 3.X Sampling Theory

[voltron7]

When you're dropping frame times down from 3 hours to 40 minutes a few days optimizing doesn't seem so bad compared to 'miss the deadline because renders haven't finished'

well put, cubiclegangster

[Morne]

From my experience so far it's in range of 3-6 for scenes with DOF and a lot of details in texture and geometry. In architectural interiors with many flat surfaces it could be above 10 or 20...

It's really easy to find a fastest shading rate for each scene, region or tile map in render mask works well.

So basically your settings is something like so:
Universal:
Leave everything at default, materials and lights at subdivs 8.
DMC min 1 /max 100

Then just play with shading rate 3-6 for heavy stuff and 10-20 or more for interiors with large flat areas?

[wyszolmirski]

Generally, yes. But don't take it as a rule. Fastest shading rate will vary from scene to scene.

Also I wouldn't call dof/mb heavy it just needs much more camera rays compared to usual architecture scenes. But overall it can be quite fast by actually lowering min shading rate (more AA/camera rays, less secondary samples/bf,lights,gloss).

[^Lele^]

I would add, for those that have time and desire to go through everything and optimize it Some users get the wrong impression that you *have* to go through all that each and every time, whereas the reality is that often the time that it takes to do all that could be better spent while the computers are working. I myself often prefer the universal settings, following the "user's time is more valuable" paradigm

Best regards,
Vlado

Hey!
People's gotta work! XD

[rjohnson33]

From my experience so far it's in range of 3-6 for scenes with DOF and a lot of details in texture and geometry. In architectural interiors with many flat surfaces it could be above 10 or 20...

It's really easy to find a fastest shading rate for each scene, region or tile map in render mask works well.

By this do you mean that you're taking a small test region and rendering out tests using different min. shading rates to see which one renders fastest?
(I guess a test area that covers worst case DOF, reflection and GI so you can make sure that the quality of these isn't compromised by the setting)

Also, does anyone know why it's mentioned in the help documentation that min. shading rate is particularly useful in conjunction with the progressive sampler? What would the relevant connection be between those two?

[peterguthrie]

did a bit of testing: http://www.peterguthrie.net/blog/201...ersal-settings comments welcome!

[vlado]

That was the general idea for that option, yes

Best regards,
Vlado

[RockinAkin]

did a bit of testing: http://www.peterguthrie.net/blog/201...ersal-settings comments welcome!

Awesome results! These are about in line with my own tests which I'm gonna try to make a writeup for as well.

Min Shade Rate is quickly becoming my new favorite parameter.