VRayRawReflection Problem

[amberspice]

Hi

Has anyone got an idea, why my VRayRawReflection element appears so grainy while the beauty pass is very smooth? Can I set different qualities for the render elements?
Thanks for any help in advance!

Tobi

[joconnell]

Hi Tobi,

When you're looking at reflections, it also helps to render the normal reflection element and the reflection filter also. What's happening here is that vray will look at the amount of reflection on each material, and if the reflections are very weak then it puts less sampling in to them. For example your ceiling material is only slightly reflective compared to your floor, so the reflections might only be contributing 10 percent to the final look of those pixels. Vray knows this while it's doing it's sampling calculations and cuts off the sampling early. The raw reflection takes all of the reflections in your scene and boosts them up to 100 percent strength, so your 10 percent reflective ceiling is being boosted to 10 times the amount it was intended to be used at. If you render the normal reflection element which shows the reflections at the level that they're actually used at to make your main beauty render, the roof reflections will likely be very, very weak.

It makes a lot of sense in terms of speed of rendering - there's no point in vray increasing the quality for something that isn't needed. If on the other hand though you mainly want to be able to tweak every aspect of the render in 2d afterwards, you might be better off making a less correct beauty render so your elements have more information in them to work with. For your glass in this case you could up your material reflection samples heavily to increase their quality, or what you could do is turn up the strength of the reflections on the glass so vray treats them as more important. It'll make your straight image look worse, but your elements will have more in them to work with.

[joconnell]

And as an aside - really nice render.

[amberspice]

Hi Joconnell,

Thank you very much for your precise explanation and for your compliment, I really appreciate!