VRay - Clean Glossy Reflections

[RobSteady]

Hi,

the following Adaptive DMC sampler setup is the only way i can get clean reflections from a glossy material. Is there another, faster way (no Adaptive Subdivs please)?

I've tried "min 1 max 100, Clr thresh: 0.002" and got noisy reflections, even with high material subdivs. "Noise threshold and Min Samples had no effect.

 

Here is the Test Scene: http://www.mediafire.com/?or6amica6gch6dy

[ATTACH=CONFIG]46320[/ATTACH][ATTACH=CONFIG]46319[/ATTACH]

Edited December 21, 2011 by RobSteady

[Chris MacDonald]

Those reflections in the image don't look particularly noisy to me.

[RobSteady]

The rendering is with the described setup (so there is no noise); i only get clean reflections when i use: min. 2 max. 3 or min. 3 max. 4 and so on...

When i use min. 1 max 50 or so and lower the color thresh. to 0,002 i always get some noise.

[Chris MacDonald]

That's because you're lowering the minimum samples to 1, as opposed to the previous set up where it's set to 2. If VRay thinks it is a suitable amount of noise (specified by the threshold parameter) then it will no longer subdivide with the antialiasing filter.

 

The higher you set your minimum samples, the higher the quality you will achieve - however this also means that vray will spend a long time on areas even if there is no noise at all. This is why the minimum should be left at around 1 or 2 and the maximum at 4 or more - render quality can then be adjusted by raising or lowering the noise threshold.

[RobSteady]

Thanks for your quick explanation.

I was just wondering, why some of the "masters" (bertrand benoit, peter guthrie) use final-setups with very basic DMC settings.

For example: min. 1, max. 6, color thresh. 0,01.

But with those settings you'll get very noisy reflections (i know it always depends on the scene you're rendering, but...).

[Chris MacDonald]

There are other ways to increase glossy quality, for example under the settings tab you can change the minimum samples on the dmc sampler (the default is 8.) to a higher number to force Vray to use more of the glossy samples within the material.

 

Example:

 

Your material has 100 glossy samples, and the DMC min samples is set to 8. This means that VRay will take a minimum of 8 glossy samples on that material - if this is deemed to have been enough to clear up any noise, it will move on rather than spend time sampling all 100 samples.

 

The "adaptive amount" also affects this. You can force Vray to use all 100 glossy samples by turning the adaptive amount to 0.

 

The fact is there are many different ways to clear up noise within VRay.

[RobSteady]

Ok, thanks!

And what is your preferred workflow?

Considering time/quality?

[Brian Smith]

might i suggest the free 1-hour vray video i recorded last year while visiting the Chaos Group building in Bulgaria. it's advanced but covers everything you need to know about critical settings like these. you could stop and play it over if it's a little fast for you. http://www.thecgschool.com/free-resources/

[RobSteady]

Thanks Brian!