Sampling tutorial for V-Ray 3.20

[vlado]

As I promised in the DMC sampling thread, here is a short video that I recorded with my (current) favourite settings for setting up sampling in V-Ray 3.20:

Best regards,
Vlado

[Morne]

Nice one Vlado
Thanks!

[flat]

SUPER Tips !!

[Morne]

I actually have a simple interior room 3m x 3m with 1 large window. Basically a cube with a hole in it lit with VRaySun and Sky. Also tried adding plane light with skylight portal, but at 2K I'm struggling to get a clean image in small amount of time.
Also tried disabling the plane light and adding a dome light with the sky inside there.
Maybe I'm just being overly optimistic to get it to less than 20 min a frame (currently about 1 hour per frame, and not yet clean)

[FSGFX]

Thanks Vlado great tips.

i assume this works also with the progressive sampler...?

[lightpixel]

Finally some really good tips! Big Thanks, vlado!

[AlexP]

This is cool, but from this starting point what do we then change to reduce noise?
MSR and clr threshold? or just MSR? or just clr threshold?

Im still under the impression only MSR should increase. (rather than decreasing clr threshold)

[Moriah]

Really helpful thanks vlado!

This is cool, but from this starting point what do we then change to reduce noise?
MSR and clr threshold? or just MSR? or just clr threshold?

Im still under the impression only MSR should increase. (rather than decreasing clr threshold)

From what i've understood MSR increase only if scene has large areas that need more sampling, MSR decrease if lots of detail. When both are present in the same scene, maintain MSR at 6, for large surfaces increase subdiv multiplier, for fine detail decrease it.
Clr threshold just for noise amount.

[AlexP]

Really helpful thanks vlado!



From what i've understood MSR increase only if scene has large areas that need more sampling, MSR decrease if lots of detail. When both are present in the same scene, maintain MSR at 6, for large surfaces increase subdiv multiplier, for fine detail decrease it.
Clr threshold just for noise amount.

Surely that then goes against the whole philosophy of leaving little work for the AA if Ive got low MSR and such a low clr threshold?

[vlado]

from this starting point what do we then change to reduce noise?

I generally prefer to decrease the noise threshold before resorting to increasing MSR.

Best regards,
Vlado

[^Lele^]

Surely that then goes against the whole philosophy of leaving little work for the AA if Ive got low MSR and such a low clr threshold?

Yes, and no.
AA remains slower a cleaning method than using specialised rays (which is the WHOLE point of having MSR in the first place.).
What Vlado is trying to say, in the video, as I understand it, is that SOME specific situations WILL NEED AA rays, rather than MSR, to be properly cleaned.
Namely (and if you look at my previous posts, even in the monster post with script and stuff on sampling, that's there too, as it's no news at all.), THIN stuff (in screen space): hair, tree leaves and thin branches, fine textures.
For those, there simply is no substitute to multiple AA Rays, so having too high an MSR would degrade performance, for no appreciable rise in quality.
In other words, no MSR will clean your super-thin geometric edges/detailed textures/moblur/dof enough with too low a number of AA rays. You WILL need AA for those.
And that is why Vlado shows the per-object trick to ignore the MSR value (which will perhaps become automatic later on).


I'm sure he'll correct me if I got it wrong (History tends to repeat itself, eheh).

[jasonhuang1115]

Thank you Vlado! And the info shared here that really help fill the tiny gaps in-between...

- Jason

[jacksc02]

Thanks for the video Vlado!
I have been using this workflow for a couple of months now and it simplifies everything PLUS I am getting faster and cleaner renders.

[alexyork]

Excellent video, thank you! I'm going to try this on a job and see what happens.

Looking forward to similar videos covering GI etc.

One request - it would be great, after you've covered the basics, to run through a real-world scene for a challenging scenario such as a space with large flat areas of glossy materials plus lots of fine details such as trees/planting/grass, with complex lighting. It would be great to see how you'd approach this.

Thanks again. Most useful!

[kosso_olli]

One request - it would be great, after you've covered the basics, to run through a real-world scene for a challenging scenario such as a space with large flat areas of glossy materials plus lots of fine details such as trees/planting/grass, with complex lighting. It would be great to see how you'd approach this.

+1 for this! The tutorial on the teapot is most appreciated, but I imagine it is a totally different story in complex scenes.