It appears that a Reflect value nearing 0,0,0 does not allow for only a very slight amount of reflection like I’m wanting. The attached image pretty much sums it up.
Simple scene. I have a cube being lit by 2 extruded planes. There is no other lighting in the scene.
Indirect Illumination=On
Extruded planes:
Both planes have a VrayLightMtl applied--one green, one blue.
Cube:
The cube has a VrayMtl applied with a diffuse value of 15,15,15. Almost black.
Setting the Reflect color to the values shown in the attached image, has the result as shown.
What am I missing to allow for finer control of the reflection amount?
Make sure you also reduce the cut-off threshold in the Options section of the material. The default value will skip the calculation of very faint reflections.
Thanks for the advice. It allowed me to reduce the reflection even more. I did think it strange that the reflection disappeared when setting the value at 2,2,2 or lower. Nice to know now how the Cutoff has an effect.
However, it seems like a Reflect value of 1,1,1 should make the reflection barely perceivable, even almost invisible. How come this isn’t the case?
Do you use any gamma correction? It will boost the colors additionally. In any case if you need to go below 1, just use a VRayColor texture to enter floating-point values.
Yes, I’m using gamma correction--trying to follow a linear workflow (see settings below). So yes, the rendered image does look brighter (gamma 2.2), but when saved I set it back to 1.0, which are the versions I uploaded above. I’ll admit, I’m still trying to understand the linear workflow concept.
I tried putting a VrayColor material in the Reflect map slot as you suggested, Vlado. It seemed to make changes to more than just the reflection though. So I figured out another solution… For the colored planes, under Vray object properties, I unchecked ‘Visible to reflections’. Then I duplicated the planes, and for the duplicates, rechecked ‘Visible to reflections’, but unchecked ‘Visible to GI’. Then I made a separate material for the duplicate planes that was less bright so I can use the duplicates as a reflection source only, and the original planes for GI only. It still seems like a Reflect value of 1,1,1 should allow for a barely perceptible reflection, but the solution I came up with gives me the result I want. It works for this simple scene at least--I can just imagine what a nightmare it would be to try to do something similar for a very complex scene.
Thanks for your responses, Vlado. Much appreciated!
My gamma settings:
(under Customize>Preferences>Gamma and LUT)
Enable Gamma/LUT Correction=checked
Display: Gamma=2.2
Materials and Colors: both settings checked
Bitmap Files: Input Gamma=2.2, Output Gamma=1.0
