Material Setup Policies

[index]

Hi,

I have two questions about Material Setup

As Tom states in this thread we were / are used to tone down 100% white to 80% in the old Vray.
" a white paper is not RGB 255,255,255 (100% white) but more something like RGB 204,204,204 (80% white) "

Is this still the recommended workflow, state of the art in Vray 5 ?

When you look at the "Understanding metalness" article, the created metals partly use very bright diffuse channels (e.g Silver)
Even iron has rgb(226, 223, 210) and looks overly bright in comparison to other materials when toning down dielectrics like in the old Vray.
In the past I did it for about everything. e.g. Client wants rgb(241, 234, 196) --> Vray rgb(241, 234, 196) * 0.8 (using brightness)
(note.. this is why the brightness is great, it doesnt change the input color values)

Also I wonder if it is recommended to use a brighter version of the diffuse for the reflection
(e.g. white color, diffuse texture, mix strength 25%) or if it is better to always use white for the reflection color.

best, index

[tomschmid]

Vray3 was much more logical with colors and it worked just fine.. why change something that worked and make it more confusing.. textures with 255,255,255 pixels in it i have to mix with 40% black to get a 80% white.. in vray3 it was 20% black to get a 80% white (so much logical).

[index]

tomschmid
Vray3 used sRGB input values for the mix strength. This was great to work with, but not matching C4D.
It's super strange that C4D asks for linear values in mix strength but sRGB values in brightness, but that's how it is.

FYI, here the formula for to convert sRGB values to linear.. you can enter that (line by line) in the python console
>>> import math # needed just once
>>> value = 0.8
>>> round(math.pow((value + 0.055) / 1.055, 2.4) if value > 0.04045 else (value / 12.92), 3)
this will return 0.604 --> to get 80% you set pure black, your texture and mix strength to 60.4%
https://entropymine.com/imageworsener/srgbformula
https://www.mathworks.com/help/images/ref/lin2rgb.html

Anyway... sorry, this is off topic....

[tomschmid]

Thanks. To your topic. Difus i never go above 80% white. Reflection i often use 100% white. Exeption is when you use metallnes because the reflection color is then used from the difus. And for aluminium a 80% white seems to dark

[RwVision]

Hi Guys,

I'm still using the same method since older Vray's - that is in Diffuse, I set the color to black and just mix the texture on 80%. Anything above clearly creates unwanted over-brights.

[tomschmid]

but in vray 5 you have to mix the texture with 60% to get the same like vray 3 with 80%. 80% in vray 5 is like 90% in vray 3

[index]

Another thing is Color Mapping... I think it is not meant to use Color Mapping anymore, you should handle over exposure in the post using the VFB.
Adding a brighter version of the diffuse to the reflection helped to make images less milky / more saturated.. but this can be achieved now by tone mapping and lookup tables in the VFB ... Atm my feeling is leave the 80% diffuse thing except if metalness is used, but don't double the diffuse into the reflection.