Skin Shader Workshop

[Hirazi Blue]

Convincing, if not altogether realistic skin shading can be very hard work. Tweaking every single detail to balance them just right can seem quite a hassle. I personally have given up on it a long time ago, but I was hoping I could interest you all in a “skin shader workshop”.

The idea for such a workshop comes from the German Softimage Forum and it’s results can be viewed here.
(edit: I totally forgot that oglu created a similar thread at the XSIBase afterwards also,
this doesn't however IMHO degrade the value of a new "similar" workshop)
To even the playing field, oglu has kindly permitted me to offer you the same model the original German workshop was based on, for non-commercial usage only, obviously.

This is not meant as a competition (mostly because we can’t afford to give away prizes at the moment ), the main goal here is to share knowledge so we can all learn something from each other. We’d expect you to be willing to share settings, maps and workflow tricks, so that others could gain some additional knowledge.

The idea is for everyone who wants to participate to download the model here and start shading. This doesn’t have to be aimed at realism, or be strictly confined to the SSS shaders as such, a convincing non-photorealistic shading method would be interesting too. And “convincing” is even harder to define than “realistic”…

[farhaad_yousefi]

awesome..i'll try it.! though i have no knowledge of sss.!! are there multiple sss shadrers in softimage.?!?!
who can explain the difference.!! ?

[Hirazi Blue]

For the purpose of Skin Shading the "easiest" way to start (but perhaps not the "easiest" way to work (?) ) probably is to use the so-called "SkinSSS Shader Compound".

This compound takes all the Fast SSS Component Shaders and bundles them in one "easy" package...

The SkinSSS shader compound packages together the Fast Subsurface Scattering Component Shaders into a single compound node to create a specialized and more complex variant of the SimpleSSS Shader Compound, and is designed to create realistic skin.

;)

[redmotion]

There is this thread over at XSIbase:

http://www.xsibase.com/forum/index.php? ... adid=34836

A certain other thread here mentions the shader discussed but I'm not sure the shader works properly with SI2010-2011.

I get this error:

' ERROR : API 0.2 error 301038: while defining phenomenon declaration "ez_sss_fast_skin": "misss_fast_shader_x" returns a struct, use "ez_sss_fast_skin::deepscatter.member"
' WARNING : API 0.2 warn 302018: while defining phenomenon declaration "ez_sss_fast_skin": type conflict: "eye" is type color, "misss_fast_shader_x" returns type struct

[Hirazi Blue]

I can confirm this shader (ancient as it is...) doesn't work with SI2011 anymore.
I couldn't even get the shader preset into the Render Tree without an "unspecified error".
But as it's "merely" a "phenomenon" maybe someone "in the know" could edit the SPDL to get it working again.
Could be just a changed shader GUID, or something...

[shushens]

It's working like a charm with 2011 x64 here.
It does throw the deepscatter.member error, but I just ignore it and everything looks wonderful.

I tinkered with the SkinSSS compound a little bit. For some reason, I could not get the back scattering to work. Same weight map, radius and depth settings give pretty good back scattering in mi_sss_fast_skin. But with SkinSSS, nothing. So I just use it with mia_material for shading eyes or other things that require sss and reflection/transparency at the same time.

There is another thing that is perhaps relevant here. It is often said that in Softimage, sss shader phenomenon could be plugged in to mia_material's additional color port, if "Scattering Only" is turned on. I have seen it written in many places. But I have no idea what it refers to. I myself can't plug any sss phenomenon to mia_material's additional color port.

Softimage developers really fancy hiding certain MR features. I think they should provide some option for n00b shaders and advanced shaders in installation time.

[Hirazi Blue]

I haven't tried them yet, but SI2011 comes with two "new" (as in: previously unexposed) MR phenomena,
that apparently do things slightly differently, so they actually may work... ;)

mental ray > Material Phenomena > misss_fast_skin_phen
mental ray > Material Phenomena > misss_fast_skin_phen_d

[izze]

I had a few hours last night and thought I would give a try. I have been using Eman's shader, which works for me in 2010 and 2011. I also tried the Mental Ray Phen_D shader this morning. Just plugging in my maps and copied the settings from Eman's shader.

I am having problems getting my vector displacement to work correctly in 2011. Is anyone else using VD in 2011?
EDIT: Never mind, VD seems to be working fine.

[Hirazi Blue]

I like the "eman" version very much...
Note to self: get the eman ez-fastskin to work on my workstation also... ;)

[Hirazi Blue]

I never was much of a map painter (or much of anything else for that matter), but now I'm looking for a convincing way to create some kind of specular map. I must have read many times, certain parts of the head are more specular than others, but I forgot which parts...
Please enlighten me...

[Deracus]

Try to check this with your own face or the face of people you meet. Usually its the area of the forehead and nose - known as T-zone - which are more specular, because most peoples skin tends to be more greasy and thus more shiny.
Lips can also be an area of increased shininess because of several reasons:
- licked them wet
- lipgloss/lipstick

If the person is sweating, then this can also be a reason for shiny skin-parts...but then its also mostly on the forehead, the nose and between nose and upper lip.

Hope that helps

[Hirazi Blue]

Ah, if all things were so easily explained...

Thanks!!! Now I can mess up my skin shading attempt with some more confidence!

[shushens]

There are many things that cause specular highlights on skin.
The skin itself has a very dull rough specular which is not shiny.
Then there is sebum secreted by the Sebaceous glands on either side of the nose among other places.
Remains of sweat on skin also causes pretty strong specular.
Glossy makeup under the eyes, over the eyelids and lipstick also cause specular highlights.

In short, you have to know where it is

[izze]

I was lazy on my first post and did not paint a spec map. So, I painted one quickly to show the difference. I color adjusted my maps in XSI so he is not so pink, also had a little fun with the Overall Color slot.

I would like to try the new MR SSS again, but the Eman shader is so perfect it feels like it would be a waste of time. Maybe someone else could get some results with it?

[Rez007]

Here is a link to an older document from Mental Images about skin shading. This might help if you haven't already checked into it.

http://www.mentalimages.com/fileadmin/u ... F/skin.pdf

[Hirazi Blue]

Yeah thanks, but I already found that...
It isn't so much the theory that bothers me, it's the practical application!