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JSlotosch
11-05-2009, 04:08 PM
Hi folks,

I´m currently reading a lot off stuff about linear workflow. That´s not such an easy theme, but there are also some nice tutorials arround, thank´s to such guys

http://www.floze.org/search/label/Six%20Tuts%20On%20Light%20And%20Shade

http://www.djx.com.au/blog/2008/09/13/linear-workflow-and-gamma/

http://3dlight.blogspot.com/2008/09/linear-workflow-for-maya-mental-ray.html

They are pretty well explained.

Now, my question is, what about "misss_fast_skin_shading" and the "linear workflow"?

If I use both, I get always a grey washed out result with much less saturation.

Does anybody off you know why this happens and how I can solve this?

Here some test renders I did, to show the difference.

http://josefslotosch.com/CG/forest_spirit_question.jpg

I hope anybody can help.

Regards,
Josef

beaker
11-05-2009, 09:06 PM
what compositor are you using?

Albo
11-06-2009, 01:07 AM
I can't test it, but probably this can help you..
http://mayastation.typepad.com/maya-station/2009/10/sss-sub-surface-scatter-shader-is-not-working-with-sunsky-system.html

JasonA
11-06-2009, 01:44 AM
are these example renders of your linear workflow gamma corrected ?

royg
11-06-2009, 02:48 AM
Your results are totally correct. You don't have those horrible, unrealistic black shadows in your linear versions (often indicative of non-linear workflow).

What you need to do now is correct your color swatches and image textures to sit in the same linear color space, i.e. add gamma nodes with the gamma set to 0.545454 (1/2.2) into your shaders.

Oh, and just re-reading your post again, you need to turn off "Screen Composite" with your SSS shader for linear lighting.

Fumetsu
11-06-2009, 07:25 AM
add gamma nodes with the gamma set to 0.545454 (1/2.2)

Numbers seem to have swapped its places :P

1/2.2 = 0.454545455 (I just type in 0.455)

tostao_wayne
11-06-2009, 09:21 AM
Josef, these are the correct results, better than the tradiotonal ones. Now the dark area doesn't seem to be a black hole.


if you are trying to get the same result that you usually get with the traditional way, don't use the linear workflow.

JSlotosch
11-06-2009, 12:19 PM
Thank´s God for you guys!
That helped me alot.

I knew that if I use sun&sky system with the misss_fast_skin shader that I have to uncheck the "screen_composite". But for any reason, I haven´t recognized that the reason for this was the automatically added mia_exposure_simple. Now it makes sense.

beaker, I just use Photoshop

Albo, thanks man this was the point!

JasonA, Yes, you can see my settings in the new picture

royg, thank´s, but is this right?
Also the color_swatches need to be corrected?
I thought if I use framebuffer with setting 0.455, they automatically would be in the right gamma space? So I need to set every color_swatch from my scene of every shader, by hand, to the right gamma?
I´ve done this and you can see the different in the picture, but I´m not sure if I´m lucky with it, as you can see with ungammered color_swatch,it looks much more pinkish than orange. You can see that the yellow leaves on his arms, doesn´t look yellow anymore. Also this is alot of work if I need to do it for every singel color swatch!
Would be nice to here your opinion.

aashroff, yeah I do, thank´s man.

tostao_wayne, yes, you are right it looks better now, just unused to me, with less saturation.

Here some pictures with the results and to show what I´ve done

http://josefslotosch.com/CG/forest_spirit_question00.jpg

http://josefslotosch.com/CG/gamma_correct.jpg

Regards,
Josef

royg
11-06-2009, 07:32 PM
royg, thank´s, but is this right?
Also the color_swatches need to be corrected?
I thought if I use framebuffer with setting 0.455, they automatically would be in the right gamma space? So I need to set every color_swatch from my scene of every shader, by hand, to the right gamma?
I´ve done this and you can see the different in the picture, but I´m not sure if I´m lucky with it, as you can see with ungammered color_swatch,it looks much more pinkish than orange. You can see that the yellow leaves on his arms, doesn´t look yellow anymore. Also this is alot of work if I need to do it for every singel color swatch!
Would be nice to here your opinion.Yes, as a general rule you do have to gamma correct every color swatch - even when you use the 0.455 frameBuffer setting, Maya will not automatically correct the color swatches. It will, however, correct the image textures for you, so you don't have to do those.

To be honest though, I don't know if it is necessary to correct each and every color swatch in the SSS shader (back scatter, epidermal scatter etc). If you prefer it non-corrected, then I'd say just leave them. I know of a lot of people that don't bother gamma correcting color swatches, they simply "eyeball" a darker color in the first place, knowing that it will come out somewhat lighter in the render.

InfernalDarkness
11-06-2009, 08:51 PM
I know of a lot of people that don't bother gamma correcting color swatches, they simply "eyeball" a darker color in the first place, knowing that it will come out somewhat lighter in the render.

Indeed, I refuse to correct my swatches. Since most of my work goes to print anyway, I'm gonna have to color-correct and exposure-correct every image on a per-image basis in Photoshop and move it to my other monitor too, so wasting time "correcting" even more things in Maya isn't efficient for me at all.

It would be wonderful to actually just print a render, straight from Maya, but this has never been an option and for many good reasons. I just set the Framebuffer to .454 and Float and do the rest in post; others of course won't be able to get away with such a simple workflow, especially animators I imagine.

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