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
  08 August 2011
Hey David,

You mention that you uncheck "Linear Workflow" and manually linearize you file textures. Does this mean you also have to manually correct the colour swatches in the Vray material (like inserting a gamma node into the "diffuse colour", for example)? What about texture nodes such as ramps etc?
 
  08 August 2011
Originally Posted by cpt_O: Hey David,

You mention that you uncheck "Linear Workflow" and manually linearize you file textures. Does this mean you also have to manually correct the colour swatches in the Vray material (like inserting a gamma node into the "diffuse colour", for example)? What about texture nodes such as ramps etc?


I was about to ask the same ... Im wondering this as well ... when I check the LW button all my materials looks like more saturated, colors, etc .... how about HDR do you have to do something with them when LW button is check? ....
__________________
LDEA Kon Kuatica
 
  08 August 2011
Originally Posted by cpt_O: You mention that you uncheck "Linear Workflow" and manually linearize you file textures. Does this mean you also have to manually correct the colour swatches in the Vray material (like inserting a gamma node into the "diffuse colour", for example)? What about texture nodes such as ramps etc?
Sometimes I do hook up a gammaCorrect node and use it to set a color, but not very often. I would do it when I want to experiment with some thing and I have a particular color in mind. In this case I want to be able to select a color from the palette and do not want to have to mentally translate it to linear. But most of the time I just enter a color in the swatch directly, then drag the value down and increase the saturation a bit. And I adjust it if my render is not how I want it. However, I still wish maya would provide the option to display swatches and the color picker through a LUT.

Texture nodes and ramps? I may insert a gamma node after a ramp, and I guess I do this fairly regularly. Same with other textureNodes. But, more and more lately, I prefer to not use procedural textures. FileTextures that you build from layers of photos and manipulation almost always have a more interesting, less 'CG' look.

David
__________________
http://www.djx.com.au
 
  08 August 2011
Originally Posted by SePu: I was about to ask the same ... Im wondering this as well ... when I check the LW button all my materials looks like more saturated, colors, etc .... how about HDR do you have to do something with them when LW button is check? ....


Yeah, with LW button checked, colors do seem overly saturated... With regards to HDRi I'd assume Vray knows whether to linearize (un-gamma) based on whether its fed an 8-bit versus a 32-bit image file (so no, you should not have to manipulate HDR files in any way). Furthermore, with LW selected, how does Vray treat 8-bit files that are intended for scalar attributes such as bump, glossiness, etc (those, of course, should be left alone).

It seems the only way to ensure that you are using a correct LWF setup is by doing it manually (as in MR for Maya)... I was hoping that the Linear workflow button would spare me the tedium.

But before I relent, and go all out 'manual', does anyone know what Vray is actually doing when you select Linear Workflow?
- what does it do to procedural textures and color pickers?
- when connecting an 8-bit file to a scalar attribute, does it apply a correction?

I know something is not working in LW mode, as colors are appearing overly saturated in my renders.
 
  08 August 2011
This is what the manual says...

Linear workflow - when this option is checked V-Ray will automatically apply the inverse of the Gamma correction that you have set in the Gamma field to all VRayMtl materials in your scene. Note that this option is intended to be used only for quickly converting old scenes which are not set up with proper linear workflow in mind. This option is not a replacement for proper linear workflow.

The last sentence is the most important I think.

@cpt_O : I think that the color inputs to the VRayMtl are the ones being corrected, but it would be very easy for you to set up a test and prove it to yourself. But why bother? "proper linear workflow" in vray is super easy compared to mentalray for maya, and "manual" amounts to 1 extra click when you create a fileTexture with an 8-bit image that you intend to use for color, so its hardly a big thing.

David
__________________
http://www.djx.com.au
 
  08 August 2011
Cool

Edit...

There are colorpickers free on the web that compensate for linear colorspace.
__________________
AKA KC / Intuition

Last edited by PerfectLine : 04 April 2012 at 06:12 PM.
 
  08 August 2011
Hey Casey, do you know how this fancy sRGB color picker was created? - python, QT or plugin? Sure frustrates me that this is possible, yet not standard in maya. Oh well.

David
__________________
http://www.djx.com.au
 
  08 August 2011
Well would it be possible to use colorEditor in a script whereby the script queries selected colour and divides it by .454 or whatever? Kind of like going through the middle-man.

Unless of course PerfectLine can shed some light.
 
  08 August 2011
sRGB color pickers... now were talking...

David,

Your'e right, LWF is more streamlined in Vray... And I know it's not too difficult to add an attribute to a file node. However, I do rely quite heavily on procedural textures. Even if its just to add extra variation on top of standard bitmaps. I gamma correct every procedural that is destined for an RGB attribute, preferring not to rely on eyeballing.
LWF in Vray is easier than MR, but still not as LWF 'friendly' as I hoped (as far as my needs go)... but I'm used to gamma nodes everywhere, being a MR user, so it's an improvement.

"This option is not a replacement for proper linear workflow" ... yeah, I'd probably take them at their word. But I will still go ahead and do some tests with LW 'on' (and 'off', using a "proper LWF") and compare.
 
  08 August 2011
Originally Posted by cpt_O: "This option is not a replacement for proper linear workflow" ... yeah, I'd probably take them at their word. But I will still go ahead and do some tests with LW 'on' (and 'off', using a "proper LWF") and compare.


I don't understand why the phase "proper linear workflow" should mean using a bunch of extra nodes and optional attributes or tools like custom color pickers.

To me, it means the application just works. Check a box to switch from nonlinear to linear, and for the most part, that seems to be what Vray offers. Is it not?
 
  08 August 2011
Originally Posted by victor: Check a box to switch from nonlinear to linear, and for the most part, that seems to be what Vray offers. Is it not?


That's what I was hoping for...but unfortunately it doesn't seem to be the case...
I've run a few test renders and it seems to only work partially...

Checking LW box will automatically correct file textures, procedural textures (ie ramps etc)... as long as you are connecting them to the Diffuse Color slot. If you connect them to other colour parameters, such as Reflection Color, no inverse gamma is applied.

I rendered 2 spheres in a purely white environment. The sphere on the right is a purely diffuse sphere with the checker file mapped to Diffuse Color. The sphere on the left is a purely reflective sphere (0 diffuse) with the same texture mapped to the Reflection Color. As you can see, its washed out... no internal correction is performed.
This render was done with LW ON, adaptation only ON and linear multiply selected, sRGB in Vray buffer ON
Attached Images
File Type: jpg testA.jpg (46.8 KB, 101 views)
 
  08 August 2011
Originally Posted by cpt_O: That's what I was hoping for...but unfortunately it doesn't seem to be the case...
I've run a few test renders and it seems to only work partially...

If that's the case, then that is a problem, but I still stand by my point that we should not be considering "proper LWF" to mean doing a bunch of extra steps that the software should be doing for us.

We shouldn't have to adjust every texture and every color under the guise of control. We should have a working option that adjusts all of them at once, and then have an override for the one or two that we want to exclude.
 
  08 August 2011
Question

(added to page 4)

Last edited by Ruis : 09 September 2011 at 07:04 PM.
 
  08 August 2011
I don't disagree with you... point taken.
Craving some 'out of the box' rendering bliss.... LWF button, enable and forget.

Either way, what I find strange is that most tutorials (and many users) that discuss Vray for Maya rendering, enable the LW option and just move on without further fuss...
Maybe I'm doing something wrong? (I am new to Vray after all).
 
  08 August 2011
EDIT....

I would look for the color picker..... if you need it.
__________________
AKA KC / Intuition

Last edited by PerfectLine : 04 April 2012 at 06:12 PM.
 
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 06:14 AM.


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