Linear workflow, Vray, and Maya

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

THREAD CLOSED
 
Thread Tools Search this Thread Display Modes
  09 September 2012
revilo3D I did post a thread in ChaosGroup regrading this...!!

http://www.chaosgroup.com/forums/vb...1535#post561535


EDIT:-
So finally doing few tests after reading this forum...
I got it solved.

LWF button does affect the render in someway, that is the diffuse channel seems to darken, it does apply (.454 gamma), someone did say that.
Thank GOD !!

Last edited by govindk : 09 September 2012 at 04:58 PM.
 
  09 September 2012
The .454 you are preparing the texture for a gamma workflow of 2.2... That part is not even about controlling the gamma.

The best way to say it is a img, in maya is defined has "linear" . . . but the thing is... IS your monitor or system you have by default set for maya "linear"?

A good example is, if your using a old type of mac, its default gamma is of 1.8, so will maya read now as 1.8 gamma as linear?

1/2.2 = .454 (or something like that...)
1/1.8 = .555 (or something like that...)

so lets imagine mayas "default" linear workflow is set up for the majority of monitors, hence gamma 2.2, but your system linear read is 1.8 gamma.

What if you are in a studio with a custom colorspace?

^.^
Joe
__________________
Portfolio
Blog
VIMEO / reel

Last edited by rip3rs : 09 September 2012 at 11:40 PM.
 
  10 October 2012
Ive tested the linear worfklow checkbox here at work and it appears that it corrects:

a) material swatches
b) incoming connections

...with the inverse of the gamma setting on the colour mapping rollout. Therefore this button will not technically correct sRGB textures perfectly. For full CG work though this is really close enough and if intergration is being done - be more careful. If you pass the backplate back through the renderer and use it - it will not be correct.

Quote: OPTION A (Longer but more accurate)
(1) Set gamma 2.2 and choose do not affect colours.
(2) Adding a texture and selecting the bit map input gamma under Vray extra node for 8-bit files - sRGB
(3)sRGB button for V-Ray Frame Buffer
(4) Adding .454 gamma node to swatches
(5)rendering in 16 bit or 32 bit exr or similar linear supported format


Quote: OPTION B (easier but less accurate)
(1) Set gamma 2.2 and choose do not affect colours.
(2) Check linear workflow checkbox
(3)sRGB button for V-Ray Frame Buffer
(5)rendering in 16 bit or 32 bit exr or similar linear supported format


I think i got that all correct
__________________
"Yeap, im certain - I spent 50hrs making sure it was a cow"

www.revilo3d.com
 
  10 October 2012
According to earlyWorm, in an other thread...this method we are doing is a wrong workflow.

http://forums.cgsociety.org/showthr...677#post7424677

The last post in 1st PAGE
 
  10 October 2012
Nope sounds right.

If your referring to the color mapping gamma attribute - 2.2. See my reply in that thread.

Image sampling optimisations is controlled largely by color and contrast. If your image is linear (dark) it might for example undersample the dark edge of a cube in shadow. When we apply a sRGB LUT it will be potentially become a visible issue.
__________________
"Yeap, im certain - I spent 50hrs making sure it was a cow"

www.revilo3d.com
 
  01 January 2013
Quick question; assuming I'm not using the "linear workflow" checkbox*, do I also want to add a Texture Input Gamma attribute (at 2.2) to file textures used for reflection and translucency (on a vray2sidedMtl)?

*note in the render globals Color Mapping drop-down I have Gamma at 1, and 'don't affect colors' unchecked (using sRGB button in the VFB to preview)
 
  01 January 2013
NO, linear workflow does not add Gamma attr to tex input node...

the gamma attr node should be added only to color tex, if i remember...

Originally Posted by Richard7666: Quick question; assuming I'm not using the "linear workflow" checkbox*, do I also want to add a Texture Input Gamma attribute (at 2.2) to file textures used for reflection and translucency (on a vray2sidedMtl)?

*note in the render globals Color Mapping drop-down I have Gamma at 1, and 'don't affect colors' unchecked (using sRGB button in the VFB to preview)
 
  01 January 2013
So it works at the material level, correcting whatever is in the diffuse slot I take it. Not at the file node level?

Because I noticed that I got slightly different reflection results when only using the check box, vs using no checkbox but gamma correcting only the diffuse texture.
I will post pictures later to show what I mean.
 
  04 April 2013
I know this is old thread, but something interesting from CHaos forums recently:

This is posted by a Chaos Group developer talking about "linear workflow" checkbox:

Quote: One questions is always asked when I talk about this setup - Why in the help file is written that this workflow is not correct - it is just because there is a tiny difference between Gamma and sRGB curve. Vray Gamma Setup and the 3DSMax Gamma setup are not 100% correct LWF just because Gamma curve is different that sRGB curve - the difference is very very small. At the end Vray and 3DSMax LWF setups will produce the same result - but with Vray setup it would be easier to work with!


I guess the same would translate to Maya and manually gamma correcting.

The only thing to remember is that the linear workflow checkbox will not apply gamma correction to environment slots, as a texture for the lights and V-Ray light material and some other things like car paint material. Its pretty obvious when it happens anyways.

So there we have it.

Last edited by Hamburger : 04 April 2013 at 05:22 AM.
 
  04 April 2013
Hey thanks for posting that.

Recently I read that we need to gamma correct our light's slots as well, now i saw a video in i believe cinema4D, where your light slot is also gamma corrected.
How important is that in VRay in Maya?
Any idea anyone?
 
  04 April 2013
Yes, if you use Linear Workflow checkbox, I believe you still have to gamma correct a texture if you are plugging it into a light. From what I gather from CHaos said anyway.
 
  04 April 2013
Right!

However I am talking about the light swatches - not texture inputs into them
 
  04 April 2013
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
__________________
CGTalk Policy/Legalities
Note that as CGTalk Members, you agree to the terms and conditions of using this website.
 
Thread Closed share thread



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
CGSociety
Society of Digital Artists
www.cgsociety.org

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump
Miscellaneous

All times are GMT. The time now is 09:42 AM.


Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.