About light cache and glossy reflections

[Reaversword]

If I am not wrong, Chaosgroup invented Light cache technique. I'm doing some render tests and still I'm learning how all works, but the thing is that I doesn't get obtain nice glossy results and appears lighting cache haves a lot to say about this, here two renders where we can see differences from 8 passes with 2000 subdivs, and other one with 12 passes and 3000 subdivs.

Take a look at the wood furnishing (you can see more and more differences, but the question issue refers to the reflection of the wood):



Besides the glossy samples on the material, and light cache parameters, we need to have activated "glossy reflections" in Vray for maya settings, but the question is:

How lighting cache influences the glossy reflections?, I mean, light cache is not only an illumination technique?. Why it affects this kind of reflections?. How could I do for improve the glossy reflections here?.

Well, I'd like to know how it works more internally than simply: if I up subdivisions, appears more "light spots" in reflections, if I up passes, they mixed more. So, why this is like is?.

[Neilg]

I take it you have 'use light cache for glossy rays' turned on...?


It uses the lightmap that was created in the reflections, instead of doing all the work into raytracing it properly. There are some settings that can clean this up, but if you've got that much reflection going on it might always be a bit visible.

[Reaversword]

Cubiclegangster, Did you referring to Vray Render Settings, Global Options, Glossy Effects?. Yes I've this option marked.

If I don't understanded bad, there is other way to do it, unmarking this option, rigth?

I did a test like this, but glossy reflections simply not appears to me, although I have in material the reflection subdivisons high ("128")... I need take this easy, gonna test again, that i'm trying to test too many things at one time...

[vlado]

There seem to be other differences between the two images besides the glossy reflections; did you change any other setttings?

Best regards,
Vlado

[Reaversword]

Yes Vlado, there is a lot of differences because I'm changing and retouching a lot of things at the same time, but the question its about the glossy reflections of the wood.


***By the way, I make a mistake in the first post, first image has 3000 subdivs and 12 passes, and second one, 200 subdivs and 8 passes (I wrote 2000 in place of 200)