Understanding DMC Sampler

[vlado]

With all these renderers popping up that are just one click buttons, the time spent having to set up the renderer is becoming outdated.

You don't have to spend that time. Just because there are buttons doesn't mean you need to push them all. Things are only complicated because people tend to make them complicated, from what I've learnt... V-Ray has universal settings, and with the progressive rendering mode in 3.0 it is easier than ever to have a one-click solution for almost any situation, if you don't want to deal with any complexities. The problem comes when, as you noted, you have an animation to make, and every second counts - and those one-button solutions won't help you there.

Best regards,
Vlado

[RockinAkin]

To be honest, I'm not entirely sure why you need a calculator even now... The max samples are either what's in the material/light/whatever, or the AA samples - whichever is higher, and this is mostly all there is to it.

Best regards,
Vlado

Well because it's not exactly intuitive for someone new to V-Ray is it?

Say a new user to has their scene's AA set to 20max, and in their image they're getting a somewhat noisy glossy reflection.
So they up their material's subdivs from 8 to 16 thinking that might help clear up the noise - but under the hood going from 8 to 16 makes no difference since both values get divided down to just 1 sample taken per AA sample.

Avoiding that following moment of 'huh?' should be the goal... and the user documentation doesn't really cover the back-and-forth nature of the Image Sampler's connection to the DMC Sampler very clearly - hence the reason I built the calculator as a learning tool.

I mean, this is all just my personal view on the matter - but I think this thread is a testament to how confusing optimizing a V-Ray render can be for newer users.

[vlado]

Say a new user to has their scene's AA set to 20max, and in their image they're getting a somewhat noisy glossy reflection.
So they up their material's subdivs from 8 to 16 thinking that might help clear up the noise - but under the hood going from 8 to 16 makes no difference since both values get divided down to just 1 sample taken per AA sample. Avoiding that following moment of 'huh?' should be the goal... and the user documentation doesn't really cover...

An excellent point, yes

Best regards,
Vlado

[trixian]

I'd also like to chime in and just mention that quite a few of these "misunderstandings" could be mitigated by some decent documentation (hint hint)

[joconnell]

In my ideal Scenario, V-Ray would have 6 values to control all sampling:

AA and DMC are NOT connected in any way, and no division of values happens - what you set is what you get.

The linking of these things is part of the advantage of vray and it's adaptiveness, if the two samplers weren't aware of each other you'd lose some of the speed. You're right though, it might make thinking about it simpler.

[Guest]

I'd also like to chime in and just mention that quite a few of these "misunderstandings" could be mitigated by some decent documentation (hint hint)

This thread has become 28 pages of very useful information, in fact any thread on these types of topics just get too long and it becomes overwhelming. A structured guide that is up to date, not too long nore too complex would be like gold dust . Perhaps in 3.0 where you have the help buttons next to each section in the render settings, there are mini guides for common scenarios?

[trixian]

Knowing that writing documentation is tedious and usually gets low priority, couldn't chaos crowdsource the labour from us on the forum?
I have an image of a wiki style site with us as editors as being pretty smart.
It can start off as a duplicate of the existing docs, and then we add pages for the more thorough stuff?

[Guest]

Knowing that writing documentation is tedious and usually gets low priority, couldn't chaos crowdsource the labour from us on the forum?
I have an image of a wiki style site with us as editors as being pretty smart.
It can start off as a duplicate of the existing docs, and then we add pages for the more thorough stuff?

I would happily get involved and help distribute it through as many channels as possible

[vlado]

For V-Ray 3.0 we are in fact migrating the docs to Confluence; it is a wiki-style system this could potentially allow several contributors.

Best regards,
Vlado

[RockinAkin]

For V-Ray 3.0 we are in fact migrating the docs to Confluence; it is a wiki-style system this could potentially allow several contributors.

Best regards,
Vlado

Great to hear!

[RockinAkin]

The linking of these things is part of the advantage of vray and it's adaptiveness, if the two samplers weren't aware of each other you'd lose some of the speed. You're right though, it might make thinking about it simpler.

I know, but I'd argue that the adaptiveness gets lost anyway since most users seem to adopt the universal 1/100 settings out of the gate.

[vlado]

I know, but I'd argue that the adaptiveness gets lost anyway since most users seem to adopt the universal 1/100 settings out of the gate.

But then you wouldn't care about the subdivs anyways, no? Unless you wanted the universal settings *and* tweak things on top of that.

Best regards,
Vlado

[RockinAkin]

But then you wouldn't care about the subdivs anyways, no? Unless you wanted the universal settings *and* tweak things on top of that.

Best regards,
Vlado

Kind of - I'd like for users to be able to set their AA samples according to scene requirements, and then be able to tune the DMC sampler in a logical and intuitive way. Yielding the best possible render times.

What I have in mind as the ideal solution would be this UI mockup:



The key is those 3 buttons in between the Image Samples and DMC Samples columns.

When either of the first two buttons are ENABLED - the DMC subdivs value gets divided by the Image subdivs value.
When either of the first two buttons are DISABLED - the samples are taken as is.

You could even get fancier by having the DMC values on the right automatically raise/lower as the Image samples value on the left is raised/lowered when the button is enabled.

The last of the 3 buttons simply links the color threshold to the noise threshold.


With this setup all settings regarding sampling are directly shown to the user in a logical, clear and uncluttered way.
And most importantly - there's never an instance where raising or lowering a value makes no difference to the resulting render.
And as an added bonus - older V-Ray scenes could be converted into this new sampler setup with just a little bit of math... so backwards compatibility isn't broken.

[vlado]

I'm not sure how the different light/materials etc. subdivs would fit into all that?

Best regards,
Vlado

[RockinAkin]

I'm not sure how the different light/materials etc. subdivs would fit into all that?

Best regards,
Vlado

Replace the light/material subdivs with a multiplier that defaults to 1.0

If you need more samples in any specific place, raise the multiplier accordingly.
The multiplier just multiplies whatever your DMC min / max settings currently are for that particular light/material/etc.

Again - intuitive and logical.