Vray render passe again

[rancax]

Hi guys, me again...i hope I'm not bothering too much

So regarding my previous post got infos but problem is still there...
In order to practically work with photoshop and vray render passes the must be 8 bit or 16 bit files...

Since in vray manual ( because chaos group ) did not put blending modes for theirs ''BACK TO BEAUTY'' & ''ADVANCED BACK TO BEAUTY'' and I just can't find for those render passes blending modes ( containing in those 2 methods for post-production )

Dans helped me alot with formula but I need a little bit more help and info if someone has it so :

1) BACK TO BEAUTY what are blending modes in 8 bit and 16 bit for :

a) Vray lightning = ?

b) Vray globall illumination =?

c) Vray reflection =?

d) Vray refraction =?

e) Vray specular =?

f) Vray SSS2 =?

g) Vray self illumination =?

h) Vray caustics =?

i) Vray atmosphere =?

2) regarding ADVANCED BACK TO BEAUTY how in the hell to recreate it in 8 bit or 16 bit mode???? ( 32 bit mode I understand formula linear dodge/add and multiply ) but blending modes change when working in 8 bit or even 16...

So, HAS ANYONE HAVE or can write about every SINGLE PASS THAT THIS METHOD USES AND ITS BLENDING MODES??? IS IT EVEN POSSIBLE TO RECREATE IT IN 8 BIT OR 16????

THNKS GUYS IN ADVANCE

[Svetlozar Draganov]

There are several tutorials on the Docs which very clearly describes how to combine render elements in order to get the Beauty result and they are:

Basic Compositing:
Lighting + GI + Reflection + Refraction + Specular + SSS + Self Illum + Caustics + Background + Atmospheric Effects = Beauty

Advanced Compositing:
(Diffuse x (Light Raw + GI Raw)) + (Reflection Raw x Reflection Filter) + (Refraction Raw x Refraction Filter) + Specular + SSS + Self Illum + Caustics + Background + Atmospheric Effects = Beauty

In both formulas:
"+" operator means that elements should be added like 1+1=2 (In Photoshop this should be ADD blending mode)
"x" operator means that elements should be multiplied like 2x2=4 (and this should be Multiply blending mode)

Since Photoshop is not a truly compositing software it doesn't have the needed tools to combine render elements properly and almost always you will see some difference between the Composition and the Beauty.
Here are the the formulas translated to Photoshop language:

Basic Compositing:
Lighting ADD GI ADD Reflection ADD Refraction ADD Specular ADD SSS ADD Self Illum ADD Caustics ADD Background ADD Atmospheric Effects = Beauty
Advanced Compositing:
(Diffuse MULTIPLY (Light Raw ADD GI Raw)) ADD (Reflection Raw MULTIPLY Reflection Filter) ADD (Refraction Raw MULTIPLY Refraction Filter) ADD Specular ADD SSS ADD Self Illum ADD Caustics ADD Background ADD Atmospheric Effects = Beauty

Regarding the bits - the more the merrier. Usually 32bits render elements should give the best result but again Photoshop doesn't have proper support for 32bit files so maybe the best way to find out which one is the best is to compare all of them and see which one gives the closest to the RGB result.

Pages in the Docs related to this topic:
https://docs.chaosgroup.com/display/VRAYNUKE/Beauty
https://docs.chaosgroup.com/display/...+%7C+RGB_Color

Here is a random tutorial I found on the web that might be also helpful:
https://cgi.tutsplus.com/articles/co...oshop--cg-4077

[rancax]

Hi Svetlozar,

and first of all wanted to thank you for your answer... and I have a couple of replies > After few clarifications I understand VRAY's formula regarding linear workflow > 32 bit files, and ready to go, no headache just add or multiply, that's o.k
Even photoshop limitation it's straightforward, but again with few basic tools available with 32 bit file at the end when you export your work to upload it to some portfolio sites ( they usually require jpg's, maybe png's ) pictures got burned... importing as linear is okay, ps vs vray frame buffer no inconsistencies what-soever,but exporting due to srbg it's burned but I have managed to go around stupid ps > just used different program which is miles away from ps...

and regarding your reply "Regarding the bits - the more the merrier. Usually 32bits render elements should give the best result but again Photoshop doesn't have proper support for 32bit files so maybe the best way to find out which one is the best is to compare all of them and see which one gives the closest to the RGB result.''...
Well man i just can not dig this! why? "cause you guys surly tought maybe someone don't want to use 32 bit files, maybe png's, jpegs on the fly ( understand totally about bit depth and why should be used ) to comp basic beauty or advanced, because vray is a product of chaos group, you guys made it, shape it, designed it, code it and all other stuff and plus people are paying good money out of theirs pocket ( I don't know what is the current price, remembered was 750 euros + ) and my oppinion is that considered all this, you know to sit down and guess between dozen blend modes in ps, waste time doing that, it's just frustrating and not very professional, if chaos group invested time to explain and to show schematics regarding ''back to beauty and advanced back to beauty'' maybe, if you guys just sat down and invested let's say hour or two to write blending modes regarding both workflows and with low dynamic range images for example then a customer who pays hundreds of dollars or euros maybe would not be in position to ''GUESS'' blending modes and waste time and money doing that...
Please don't get me wrong, I'm not here to tell chaos group how to manage their company, far from it...it's just a constructive critique from every day user, from end user which I think is the best judge about all products today on a market...

Anyway thnks for your time and your answer I know you guys are very busy
cheers