Understanding dmc sampler tab connection with other image samplers

[jaik]

Hi, i m digging deep in some vray tabs. please help me out. How "Image Sampler (aa)" is connected with "Global DMC or DMC sampler tab".Is four of samplers say-fixed adaptive, adaptive subdivision, progressive are connected default to Global DMC rollout or some of them influenced by Global DMC. i have read many times on vray official help about Global DMC but unfortunately not got my answer clearly. Is Gobal DMC rollout will be used in all condition behind the scene when evaluating all values (aa, dof, ii, area light, glossy refl-ref, translucency, mb) whether i use any listed image samplers that vray offers. In earlier version of vray doesn't have "Use DMC sampler thresh." check box. tabs are renamed bit confusing to understand. previous have named "V-Ray::Adaptive DMC image sampler" and new have named "Adaptive image sampler" so what is difference between those, its looks both same in parameter it have. old have "V-Ray: DMC Sampler" new have"Global DMC" its annoying.is rqmc dmc sampler have their own algorithm. Here i need help from you guys:

Is vray dmc sampler tab affecting my aa sampler if i choose adaptive subdiv sampler?
Is vray dmc sampler tab affecting my aa sampler if i choose fixed sampler?
Is vray Global DMC tab affecting my aa sampler if i choose progressive sampler?
Is vray Global DMC tab affects my Irradiance, Light Cache, Brute Force, Photon subdiv if i bump up in Global subdiv multiplier in global dmc or dmc sampler tab?
Is vray Global DMC tab always shoot "min samples" for all area shadow, gi, bruteforce gi, reflection-refraction?
Please correct me if i am wrong, as far as i know Vray DMC sampler affects dmc aa sampler.

Thanks, i will be very grateful

[tashko.zashev]

Hi,

Actually many things related to the image sampler has changed since the 2.x release > 3.x and latest service pack 3.3.
There is a lot of internal optimizations and this has also reflected to the V-Ray UI.

I will try to answer your question below:

In earlier version of vray doesn't have "Use DMC sampler thresh." check box.

This option was removed from the UI in the latest releases since changing the Global DMC Noise threshold is actually rarely needed. The idea is Color threshold to be used instead.

tabs are renamed bit confusing to understand. previous have named "V-Ray::Adaptive DMC image sampler" and new have named "Adaptive image sampler" so what is difference between those, its looks both same in parameter it have. old have "V-Ray: DMC Sampler" new have"Global DMC" its annoying.is rqmc dmc sampler have their own algorithm.

We did some reorganizations to the UI and some parameters and roll-outs has been also renamed.

Is vray dmc sampler tab affecting my aa sampler if i choose adaptive subdiv sampler?

The AA set to Adaptive will affect the DMC sampler only when "Divide shading subdivs" is enabled.
For more information about how exactly the divide shading subdiv. works and examples please refer to our docs:
http://docs.chaosgroup.com/display/V...+Anti-Aliasing > Divide shading subdivs
Moreover for the latest update we have introduced the new VBAS - Variance-based adaptive sampler and Automatic sampling of lights and materials.
So there is no need to set subdivisions manually for materials, lights..

Is vray dmc sampler tab affecting my aa sampler if i choose fixed sampler?

The Fixed image sampler doesn't affect the DMC sampler.

Is vray Global DMC tab affecting my aa sampler if i choose progressive sampler?

It is the same as Adaptive sampler has been chosen.

Is vray Global DMC tab affects my Irradiance, Light Cache, Brute Force, Photon subdiv if i bump up in Global subdiv multiplier in global dmc or dmc sampler tab?

Global Subdiv multiplier affects everything, except for the light cache, photon map, caustics and AA subdivs. Everything else (irradiance map, brute-force GI, area lights, area shadows, glossy reflections/refractions) is affected by this parameter.
Assuming Use Local subdiv. is enabled.

Is vray Global DMC tab always shoot "min samples" for all area shadow, gi, bruteforce gi, reflection-refraction?

Not always, it depends on the AA and DMC setup. Usually there is no need to adjust this parameter.
For better understanding about the amount of samples for particular light or material in 3.3 we have added subdiv. calculator beside each subdiv. parameter.

[jaik]

Thanks a lot for helping me.