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Poser - OFFICIAL F.A.Q (Last Updated: 2024 Dec 22 10:18 pm)



Subject: Skin tones and SSS


cedarwolf ( ) posted Sat, 01 June 2013 at 11:57 AM · edited Mon, 23 December 2024 at 4:12 AM

I've caught the SSS fever, but I'm being side-tracked by having to learn the terminology and the inability to find correct shaders for many ethnic skin tones, and in particular, Native American skin tones. As lovely as some of the commercial packages are, they are DEFINITELY not Native American no matter what the advertising copy says.

I can't model...yet...so I have no way to correct facial bone structures but I can at least help out on the skin tones. Here is my research so far:

Pantone Codes for Skin Colors: http://www.athenna.com/artist-aims-to-catalog-all-possible-skin-tones-using-pantone-color-chart/athenna/web_design/teoria-de-design/
More Pantone Codes: http://anthrocivitas.net/forum/showthread.php?p=202209
25 Useful Skin Textures http://www.athenna.com/25-useful-skin-texture-collection/athenna/web_design/teoria-de-design/
More Pantone Skin Codes http://humanae.tumblr.com/
Color codes for Native American skin textures Pt. 1 http://encycolorpedia.com/592720
Pt. 2 http://encycolorpedia.com/421d18

I highly recommend Pt. 2 as it allows you to click on a color and it takes you to that as the median color and gives you visual references and all the codes for the colors shown.

Please, and this comes from all the Native American artists I know (and being in the Capitol of the Cherokee Nation I now a lot of them), take some time and don't try to pass of a European with a mild tan as a Native American.

The same when modeling materials for N.A. characters. Go to a good photo archive and look at the actual gear. Each Nation has their own version of what things are shaped like and how they are designed. DO NOT push television "injun" materials as actual Native American materials. At least be so good as to add the disclaimer "based on a XXXX design" near the top of the advertising copy so the consumer, and the viewer, knows it is not intended to be offered as correct.

If you are going to add beading, check archives for patterns and don't just toss down what you've seen in movies or television. Most of that stuff comes from countries that have never seen the original material and don't care as long as they sell product.

Hopefully this will create a dialogue and some good discourse without racism or intolerance. We, the Native American community, may not always look like what you THINK we should look like on the outside, but we know our own culture and ask that you respect it as you would your own.


LaurieA ( ) posted Sat, 01 June 2013 at 12:49 PM · edited Sat, 01 June 2013 at 12:58 PM

You need to understand that ppl that sell/give away NA items/skins/whatever, are doing the best they can and are NOT trying to offend anyone nor are they racist or intolerant. It doesn't help when some ppl get offended at every little thing. Best to be offended when you KNOW someone is trying to offend you.

Man, the world needs an enema.

FWIW, I would love to see the same stuff you mention, but since the Poserverse pretty much runs on fantasy, you have to understand when "creativity" and someone's misguided conceptions enter in.

Insinuating that ppl are being "racist" or "intolerant" makes you look pretentious and maybe even a little intolerant.

Laurie - "The one who doesn't seek to offend anyone, yet normally offends most"



Gremalkyn ( ) posted Sat, 01 June 2013 at 1:22 PM

I took it as a "please don't" rather than a "you better."


cedarwolf ( ) posted Sat, 01 June 2013 at 1:49 PM

It actually WAS a "please don't" and not a reverse racism rant.  One of the most important things I teach my college students is that the need for research and evidence is paramount in any undertaking.  To me, and I make no claims for anyone else anywhere else (and I hate the use of blind inclusives), my post was simply a request for people to take a little time and think about things.  I would never "assume" to stereotype another group because I know better, being mixed race, than to make overwhelming assumptions about any group.

Yes, we tend to be a bit touchy about these things, but by and large, there wasn't a concentrated effort to commit genocide on Europeans by invading forces and then having the survivors rounded up into concentration camps where many are still detained today.  They are called "Reservations" and, by and large, they are located in the most inhospitable areas possible in an orchestrated attempt to finish the job through benign negligence.  

Compiling the list was simply a way of making a resource available to those who might want or need it to more accurately portray a certain population.  It was not an attempt to create dissent.  If that is the discussion that is wanted, we can take that discussion off this forum and find one where we can all rant, call each other names, make bold statements, and whatever comes along.  This was not my point in my original post.

Thank you for patience and tollerance.


LaurieA ( ) posted Sat, 01 June 2013 at 2:10 PM · edited Sat, 01 June 2013 at 2:16 PM

Quote - Yes, we tend to be a bit touchy about these things, but by and large, there wasn't a concentrated effort to commit genocide on Europeans by invading forces and then having the survivors rounded up into concentration camps

Well, I can think of some Europeans that were, but I won't go there.... Either way, it's neither here nor there - the fact remains that no one set out to offend any one person or group.

I did see the post that initiated this one, and you got offended at the person in that thread and he didn't do anything but ask for help with his project....

Maybe we're all a bit touchy...too touchy.

Laurie



kobaltkween ( ) posted Mon, 03 June 2013 at 7:35 AM

Content Advisory! This message contains nudity

file_494930.jpg

It's hard to do proper non-European skin tones with Scatter on Skin, which is what most people use for SSS in skin.  That scatters a pale pink, whcih can work for some light skin, but is more "off" for darker tones or less pink ones.  That's actually explicit in Skin and Skin2.  They were only designed for light, pink skin. 

What can do is separate out your dermal and subdermal scattering.  Dermal should change with your skin type and melanin.  It should basically be a light, desaturated base with different amounts of yellow/tan (depending on melanin), and be wide but not deep.  Subdermal should be red and less wide (flesh being denser than skin) but deep. 

Personally, I use two Custom_Scatter, some edge blend, and some other tricks to make skin.  I mix based on the skin type and tone.

Here's an example of the Elite Marie texture with my skin shader (sorry, it's only on deviantARTT right now):

http://kobaltkween.deviantart.com/art/The-Look-II-348227822

And I've attached an image with a more tan texture than that one.   I sort of hacked it together by mixing maelwenn's Vanessa and J.King's Alayeh together.  It's still probably darker and flatter than you're thinking of, but I thought I'd include it as an example of what I've done with this method.

Neither are Native American skin tones, I realize, but what I'd consider a fairly realistic darker skin tones.   I also realize that only addresses the material.   I've only bought one NA texture set, and I can't quite say the skin tone is realistic.  Most I see just don't seem quite right in hue or saturation, so I can understand your concern (not quite right to me is probably glaring to you). 

That said, I also find it hard to find very pale textures, but I often make do with what I have and Photoshop.  As long as I have a decent detailed base, some decent skin brushes (there are tons on the Web) and some idea of the tone I want to achieve, I can do pretty much anything I want.



Keith ( ) posted Mon, 03 June 2013 at 11:01 AM

Quote - Please, and this comes from all the Native American artists I know (and being in the Capitol of the Cherokee Nation I now a lot of them), take some time and don't try to pass of a European with a mild tan as a Native American.

And I might suggest that statement still implies a limited number view of what skin tones are present in the aboriginal populations of the Americas, especially after a few centuries of people doing what people have always done when they meet other people.

I live in an Inuit community, and amongst the Inuit beneficiaries (that is, recognized as Inuit under their land claim), there are several blond-and-blue eyed Inuit, others that look like they just came off the plane from Beijing or Tokyo, some that look stereotypically "Indian", and one who, were she in Toronto or New York, would be called black and no one would look twice.

(Which also leads to amusing things like one woman I thought for years was Inuit because she looked so stereotypically Inuit, and wondering why she had such a weird accent: she was actually born in Burma.)

I've seen the same thing amongst many of the other First nations people I meet and deal with regularly.



cedarwolf ( ) posted Mon, 03 June 2013 at 11:22 AM

Thanks, folks, and I appreciate all the input.  It's like here where I'm at, Keith, Cherokee goes from escaped Viking to dark as red river mud due to assimilation.

Again, I appreciate the input.  Some of the technical stuff I don't understand...yet...but I am beginning to see the actual difficulties to some of these problems.  Add to the mix palms of hands, soles of feet, how much sun some areas get vs. how much others get and you wind up with a whole mixed bag.


mackis3D ( ) posted Mon, 03 June 2013 at 6:53 PM · edited Mon, 03 June 2013 at 6:55 PM

Quote - One of the most important things I teach my college students is that the need for research and evidence is paramount in any undertaking. (...)

Yes, we tend to be a bit touchy about these things, but by and large, there wasn't a concentrated effort to commit genocide on Europeans by invading forces and then having the survivors rounded up into concentration camps where many are still detained today.

I feel ashamed about your ignorance to the genocide on 6 million Jews by Germans and their corresponding invading forces all over Europe until less than 70 years ago. Probably more than you about missing the correct skin textures for Native Americans (by the way the kids in the Poser world don't look like real kids and Victoria 4 not like a real woman...). For your college students I hope that is not typical for your history knowledge and you were just a "bit touchy". I mean don't you know from which language "concentration camps" comes from originally?


Latexluv ( ) posted Mon, 03 June 2013 at 7:02 PM

Quote - It's hard to do proper non-European skin tones with Scatter on Skin, which is what most people use for SSS in skin.  That scatters a pale pink, whcih can work for some light skin, but is more "off" for darker tones or less pink ones.  That's actually explicit in Skin and Skin2.  They were only designed for light, pink skin. 

What can do is separate out your dermal and subdermal scattering.  Dermal should change with your skin type and melanin.  It should basically be a light, desaturated base with different amounts of yellow/tan (depending on melanin), and be wide but not deep.  Subdermal should be red and less wide (flesh being denser than skin) but deep. 

Personally, I use two Custom_Scatter, some edge blend, and some other tricks to make skin.  I mix based on the skin type and tone.

Here's an example of the Elite Marie texture with my skin shader (sorry, it's only on deviantARTT right now):

http://kobaltkween.deviantart.com/art/The-Look-II-348227822

And I've attached an image with a more tan texture than that one.   I sort of hacked it together by mixing maelwenn's Vanessa and J.King's Alayeh together.  It's still probably darker and flatter than you're thinking of, but I thought I'd include it as an example of what I've done with this method.

Neither are Native American skin tones, I realize, but what I'd consider a fairly realistic darker skin tones.   I also realize that only addresses the material.   I've only bought one NA texture set, and I can't quite say the skin tone is realistic.  Most I see just don't seem quite right in hue or saturation, so I can understand your concern (not quite right to me is probably glaring to you). 

That said, I also find it hard to find very pale textures, but I often make do with what I have and Photoshop.  As long as I have a decent detailed base, some decent skin brushes (there are tons on the Web) and some idea of the tone I want to achieve, I can do pretty much anything I want.

 

I would like to see the node set up on this one! I am quite frustrated by the scatter node setups that are around because they seem to take my textures and lighten them and don't get me started on the specularity being way, WAY too much.

"A lonely climber walks a tightrope to where dreams are born and never die!" - Billy Thorpe, song: Edge of Madness, album: East of Eden's Gate

Weapons of choice:

Poser Pro 2012, SR2, Paintshop Pro 8

 

 


kobaltkween ( ) posted Tue, 04 June 2013 at 2:11 AM

Quote - Add to the mix palms of hands, soles of feet, how much sun some areas get vs. how much others get and you wind up with a whole mixed bag.

That's really tricky, because most of what we think of as "realism" is generally from photos rather than life.  Most of the photos and film we see are of people with quite a lot of make up.  Most of the media we look at are highly post produced.  I've done images with Blackhearted textures that looked odd to me because he made his textures so realistic that the outside of the arms were very red and darker, while the inside was much paler and less red.  That's quite natural for an outdoors, atheletic person, but can look unusually uneven in a render.

At the end of the day, you have to make your own judgement about what looks right.  Once you do, don't be afraid to edit textures you own to look like what you want.  Just don't save over the originals and don't redistribute them.  If you use Photoshop, adjustment layers can give you a non-destructive transformation that you can copy to other maps.  You can use other textures, flood fills, and seamless skin patterns as overlays, and then use masks to non-destructively vary their effect.   All of those are easy to copy to other documents, so that you can make your textures consistent across UV maps.  If you paint corrections or changes on top, just avoid the seams and you'll be fine.

As for real world ethnicity being a complex issue, I considered that a given and beside the point of this thread.   There are tons of realistic characters of visibly European heritage.  The ones that are supposed to visibly show any other type of heritage are often much less realistic, IMHO and (based on the original post) the opinion of the OP.

I've seen many characters that get darker tones inhumanly wrong to my eyes (wrong hue and saturation, like I said).  I've seen many with burned in artifacts that make them problematic with my materials.   Even in lighter shades, there are certain skin types and hues I've found difficult to obtain.  Just considering different types of textures, there are huge gaps in my library that I've deliberately sought to fill, and been unable to.   All of those types are particular to non-European ethnicities.



kobaltkween ( ) posted Tue, 04 June 2013 at 3:23 AM · edited Tue, 04 June 2013 at 3:32 AM

Oh, and just to say, I don't mean that looking unrealistic to my eyes is some sort of sin or inherent problem.  There's lots of quality characters out there that look great in other people's works, and just don't work for me.  I'm just trying to say that I think I understand the issue that cedarwolf brought up, and that I've experienced it myself to some extent.   I'm hoping that sharing the small steps I've taken to address it are helpful. 

Oh, also to clarify- I mentioned not redistributing for any newbies that come across this thread and get the wrong idea.  I don't mean to imply that anyone posting so far wouldn't know that or would redistribute someone else's edited textures. Unless they were a merchant resource, that is.

Latexluv- I'm working on a reply.



kobaltkween ( ) posted Thu, 06 June 2013 at 8:28 PM

Quote - I would like to see the node set up on this one! I am quite frustrated by the scatter node setups that are around because they seem to take my textures and lighten them and don't get me started on the specularity being way, WAY too much.

OK.  I know no one else has posted and I'm taking over this thread, but I want to answer Latexluv's question.

Yeah, that is the problem with using Skin and Skin2.  They're both very skin like and not very flesh like, so they're a lot more translucent and easy to blow out than solid flesh. 

I'm not sure how much looking at my skin material would help you make your own.  Largely because I've got my own approach to different aspects and they're all kind of mixed together in that.  Let me try breaking it down into basic components:

  • Diffuse color: Base diffuse texture unaltered (assuming I don't want it to be a little paler or darker or whatever)
  • Dermal SSS color: Base diffuse altered to be lighter, much less saturated, and more yellow/tan
  • Subdermal SSS color: Base diffuse altered to be almost pure red in hue (keeping it somewhat orange just to avoid the lobster look)
  • Generated SSS Map: I get the SSS amount by dividing the red component of the diffuse tex by the total value of the diffuse tex.  Then I boost it a bit.  This sounds complex, but it's just a few 3 nodes: image, comp node, and regular (not color) math node.  Divide (1.25 * Comp Node (Component = 0, color = Diff Tex) / 3 * Diff Tex) 
  • Edge Blend to give more dermal scattering and less subdermal at the edges: I use medium to dark grey inner, light grey outer, very low attenuation (~ 0.05)
  • SSS: One or more Custom Scatter nodes.  At present  I use a single Custom_Scatter node, with the appropriate controls on different parts.  My surface color is the diffuse map.  My scattering color is a mix of my dermal and subdermal colors defined by the controls described above.  My scattering distance (higher for dermal, lower for subdermal) is controled similarly (Math node to set base and additional amount with control plugged in).  My prescatter color is a mix of white (no change for dermal scattering) and dermal scattering color (for subdermal scattering) based on the above.  I plug all of this into Ambient Color, so that I can use Ambient Value to control the amount of SSS.
  • SSS amount:  I use this to control the Ambient Value (SSS amount) and Diffuse Value (inverted, to control the diffuse amount.  I keep both Ambient Value and Diffuse Value below 1.
  • Fresnel Blend to control specular intensity and reflection amount: I give it an IOR controlled by the spec map (if there is one)
  • Reflection: I use a softness of 6 and quality of 0.6, which seems to render OK.  I had problems with grain that these settings seemed to fix.
  • Fresnel controlled specular: I use a simple specular node.  Blinn's eccentricity is Fresnel, but in reverse (higher value is more Fresnel and lower IOR) and with a relationship to IOR that's unclear to me.  So I avoid it.  If I really want something to look wet, I'll use Glossy.
  • Bump (if it's there)
  • Displacement (if it's there)

It can get a little more complex if I have masks and different types of materials (lipstick, water, etc.), but that's basically it.



Latexluv ( ) posted Thu, 06 June 2013 at 9:15 PM

I'm saving this description but could I see a screenshot of the nodes? This would help tremendously. I've got dyslexia and sometimes written descriptions do not make sense to me. Thanks so much for taking the time for this description. I've been having a terrible time with the specular in all current shader setups. It's just not realistic to me. It makes the figure look like she's been oiled up. I'm looking for a dry skin specular look and not having luck at it.

"A lonely climber walks a tightrope to where dreams are born and never die!" - Billy Thorpe, song: Edge of Madness, album: East of Eden's Gate

Weapons of choice:

Poser Pro 2012, SR2, Paintshop Pro 8

 

 


lmckenzie ( ) posted Fri, 07 June 2013 at 3:10 AM

Frankly, I didn't see any insinuations in Cedarwolf's comments, just a sincere request. The same could apply to African, Arab or any other culture. If prople are going to agonize over "realism," why not strive to depict these things accurately? I think It really does have to be part of the artist's motivation though. Most buyers are unlikely to know the difference unless they are familiar with the culture in question. It's no different from the fact that most people are not going to know (or necessarily care) about the finer points of accuracy in a military model etc. We do have to accept the reality that after generations of Charley Chan, Chief Screaming Eagle (or even Jersey Shore) etc. people have distorted images. So much of what we "know" about people and places outside our experience is based on popular culture or extremely limited examples.

There's no malice involved in most cases, just people not knowing what they don't know and not necessarily beint too motivated to alleviate ouir ignorance. I'm not sure how many people are going to take the time to really authenticate their designs, but it certainly doesn't hurt to voice the idea. With the internet, the resources are available, but even then you probably have to put in some effort to separate the wheat fro the chaff.

The point about fantasy is true. In many cases, people are probably just trying to make something that evokes a particular theme, and hitting on some key triggers - tack a few feathers and beads on some pants and its Native American, add a turban to your outfit and its Indian etc. Likely much of the Arab themed stuff we've seen in the past few years isn't completely accurate either. It would be nice if people would add a disclaimer ala "not to scale," but that's probably not going to happen. There's nothing wrong with that. People are free to create the art they want and shouldn't be required to slavishly strive for accuracy. OTOH, if someone offers advice on that would garner you a 'wow they got that right' from people who know, then that's probably a good thing, whether you choose to follow it or not. I've seen far worse 'you've got to render with X,Y,Z or your images are crap' posts.

I doubt that anyone is trying to be offensive. It's more like not coming from cultures so far removed from their traditional roots and where such things have been replaced by mass culture, they can't imagine anyone being offended. If you do care about such things, you're likely to be labled as overly sensitive. Somehow, we need to find a median between embracing diversity and glorying in our homogenziation. If we can't get that right here, there ain't much hope for the rest of the world.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken


FaeMoon ( ) posted Fri, 07 June 2013 at 7:34 AM

Quote - Thanks, folks, and I appreciate all the input.  It's like here where I'm at, Keith, Cherokee goes from escaped Viking to dark as red river mud due to assimilation.

Again, I appreciate the input.  Some of the technical stuff I don't understand...yet...but I am beginning to see the actual difficulties to some of these problems.  Add to the mix palms of hands, soles of feet, how much sun some areas get vs. how much others get and you wind up with a whole mixed bag.

 

Actually soles of feet and palms do not have nearly as much melanin in them, like hardly any to none, so that is why they are much lighter than the rest of the skin on a darker skinned person.


cedarwolf ( ) posted Fri, 07 June 2013 at 10:37 AM

I did not know that, DA.  I just supposed that wear and tear on the tissue, callousing and such, would change the pigmentation.  Thanks for the tip.

@lmckenzie: Thank you!

Still can't figure this stuff out quite yet, working my way through some of the tutorials, and DS4.6 seems a bit...tricksey.


kobaltkween ( ) posted Fri, 14 June 2013 at 6:49 PM

Oh!  DS is very different than Poser in terms of materials.  There are aspects of that shader I described you can't do without nodes.  DS does have nodes, but they're much more complicated and much, much less documented.  Also, you can't implement linear workflow with DS without Luxrender, which means the shader will always be incorrect. 

Regular workflow drops colors out of the gamut, makes midtones muddy, blows out light values, and under exposes dark values.  I've seen people almost entirely mitigate everything but the gamut issues (can't do anything about those) with materials, lights, and postwork.  But that's a scene by scene solution, not a consistent one.

Also, the more elements there are to your shading, the more incorrect everything becomes without linear workflow.  2 SSS elements, diffuse shading, reflection, specular, and some form of bounced lights is a lot of elements to have work incorrectly.  Add in the fact that darker skin tones means a wider range of values, including the mid to darker range where regular workflow really starts going wrong, and its just really, really difficult to do well.  Not at all impossible, just hard.

Latexluv -  Showing my nodes means making sure of some particular shading details.  I'm testing some specific variations and combinations of properties right now.



icandy265 ( ) posted Sat, 15 June 2013 at 9:31 AM

file_495218.png

Sorry to be off-subject (sorta) but I just wanted to thank **kobaltkween** for the advice...

I tried it, mine was quite a bit different then yours, but it did use 2 scatter's with one hsv (making the original texture more yellow and desaturated) plugged into scatter #1, and another hsv (making the original texture more reddish-pink and darker) plugged into scatter #2 and both scatters blended with a blender node and plugged into a second blender. Then that blender was plugged into a color_math along with a blinn (with an edge_blend plugged into reflectivity) and then the color_math plugged into Alt_Diffuse... I prefer Alt_Diffuse cause when I use the Ambient channel it caused V4 to glow. Then of course the bump was plugged into a Math_Functions with Value 1 at 1.0000 and Value 2 at 0.5000 and then plugged into the bump channel... The blinn node settings are:

Eccentricity: 0.400000

SpecularRollOff: 0.200000

Reflectivity: 1.000000

Anyways... I never would have known that you could blend 2 scatters successfully if it weren't for this thread, so I'm very appreciative... Thanks :)

Btw the skin texture is Azelea by Raiya at DAZ... And my own character (dial-spun) morph...


Bill1200 ( ) posted Mon, 17 June 2013 at 6:59 PM

Has anyone tried playing with the textures and saving different (lighter or darker) versions, then loading them in the materials room?


hborre ( ) posted Mon, 17 June 2013 at 8:40 PM

@icandy265: would it be possible to upload an mt5 with the node arrangement for closer inspection?  The double scatter is intriguing.


icandy265 ( ) posted Tue, 18 June 2013 at 1:14 AM · edited Tue, 18 June 2013 at 1:15 AM

@hborre: Here ya go... I removed all the image map path's, so now they are just blank "image" blocks, so just simply insert the texture map of your choice... As usual just remove the "txt" extension (so it just says .mc6 instead).

I kept all the other material set-ups in there as well (mouth, eyes, etc) but of course you can simply change those or use cr2Editor or a text editor to edit the file so it only has the skin zones... it's up to you.

I hope this helps

P.S: @Bill1200: I'm going to post another pic in my next post :)

EDIT: Wouldn't let me attach file so will upload it to 4shared and get right back to ya... sorry


icandy265 ( ) posted Tue, 18 June 2013 at 1:36 AM

file_495307.png

Okay here's the file... I decided to include the lights I used also... :) Hope this helps...

http://www.4shared.com/zip/0TJiHtGb/DblScatterSkinMat-01.html

 

P.S: Here's a render with the same shader, just a darker texture (KENDRA for V4 by LRP; now known as J. King over at DAZ)


Eric Walters ( ) posted Tue, 18 June 2013 at 1:51 AM

I would love to play with this-but the DL seems to keep wanting me to buy an account.

Or if I DO get the free DL- it has a 20 second wait-that never actually changes from 20 seconds. Any chance you could use a different sharing service? Thanks!

Quote - Okay here's the file... I decided to include the lights I used also... :) Hope this helps...

http://www.4shared.com/zip/0TJiHtGb/DblScatterSkinMat-01.html

 

P.S: Here's a render with the same shader, just a darker texture (KENDRA for V4 by LRP; now known as J. King over at DAZ)



icandy265 ( ) posted Tue, 18 June 2013 at 1:56 AM
hborre ( ) posted Tue, 18 June 2013 at 9:16 AM

Thanks.  Hopefully I will get a chance to play with it this evening.  Next time, upload the file with an added txt extension (i.e., Myfile.mt5.txt).  This is perfectly allowable; all the we need to do is D/L and remove the txt extension.


icandy265 ( ) posted Tue, 18 June 2013 at 8:38 PM

@hborre: I tried that, it wouldn't let me?... Maybe I did it wrong somehow... Sorry 'bout that. Will try again next time hehe


Eric Walters ( ) posted Tue, 18 June 2013 at 9:20 PM

Thanks! That one worked. I'll do some playing later. The style of SSS described in the earlier posts is VERY simililar to some I had working in Lightwave a few years ago.

I was able to create truly Green skin-with Green scatter-something I've been missing with Poser! In LW I was working with Dermis, Epidermis, and Diffuse layers. It CAN be tricky and is light dependent-whereas Poser Scatter and Skin 1 and 2 work with any lighting. And LW 11 (10?) introduced something similar to Poser's skin-but a great deal more flexible-with secondary scatter for instance

Perhaps we should ask SM to release a Skin3, 4, and 5 representing different skin colors?

 

Quote - Here ya go... I hope this one works better:

https://skydrive.live.com/redir?resid=A249268012FACC8C!189&authkey=!AJtEshGiVO3jcs0



kobaltkween ( ) posted Wed, 19 June 2013 at 3:41 AM · edited Wed, 19 June 2013 at 3:49 AM

Please forgive me for the long post.  I don't mean to be impolite, just informative.  Please feel free to ignore any information you don't find useful.

Bill1200 - I edit my textures a fair amount, just to get different skin tones out of textures I already like.   Darker skin textures tend to fair worse with EZSkin style shaders.  That's why I made my own shader in the first place.  Light skinned characters looked great, but darker skinned ones looked very weird to me.  A dark skin should be brighter/higher valued in the light, not less saturated- which is what adding white will do.

icandy265 - Nice use of double scatter!  It's simple and clean.  I totally get why you're using Alt Diffuse rather than Ambient.  I like having the separate Value control for possible diffuse mixing, but Alt Diffuse is more elegantly simple.

I just thought I'd pass along a few warnings about some of the things you've done that have sometimes caused me problems in my own shaders in the past.

The first and most basic is using HSV to hue shift.  You should be able to do this.  If Poser's HSV node worked like Blender's (my other weapon of choice), it wouldn't be a problem.  But for what is (to me) completely unapparent reasons, the hue shift on the HSV node doesn't act like HSV in Photoshop.  The results are more volatile.  Sometimes it works, and sometimes it makes blotches of crazy color on your map.  IIRC, the old Alice texture by Aery Soul used to have this weird green blotch at the lips (and other redder places) when I did pretty much the same hue shift you did to make the subdermal map.

Which isn't to say don't use hue shifting.  If it works, don't worry about it.  Most of the time, it's not a problem.  But if you use it and get weird blotches of a color that doesn't make sense, that's why.  I've given up figuring out which textures it likes and which it doesn't, so I use Blender and color multiplying and other tricks to deal with the hue part.  So if you run into that problem, you can get around it.

The second is really minor.  You've used the same conservation of energy technique that's in EZSkin2, which is to use your Blinn as a single channel mask for your Diffuse and SSS shading.  This works great as long as Blinn is single channel, which, since most people use white directional lights, it usually is.  Years ago, when I was first trying to make my own skin shader, I tried this and got some weird and severe color problems in certain situations.  The problem stemmed from my use of colored lights, which means a colored Blinn.

When a color is made single channel, it's averaged.  So if there's, say, 100% Red and Green, and 0% blue,  it will average out to about 66% grey.   If your Blinn is the pure, bright yellow described above, and you do a single channel mask of your diffuse and sss, there's going to be much less blue than there should be and much more yellow.

That said, almost everyone uses EZSkin2 and I've never seen the problem in anyone else's renders.  I don't think it will necessarily present you with issues.  I'm just mentioning it because I spent ages fighting that problem in my test renders way back when before figuring out its cause.

The simplest solution to that is not to worry about CoE.  Specular nodes are just fake reflections.  It's not like they can be "correct," because they're inherently fake.  The more complex solution is to do CoE with true color math (subtraction).  Just make sure to Clamp your Blinn subtraction if you go that route.  If the Blinn goes over 1 (bright or close enough lights will do this), and you don't clamp the subtraction, you get negative colors and wild looking results.

To everyone-  For my own crazy, perfectionist reasons, I've managed to test myself into an entirely new skin shader.  Which means more testing to go (finalizing some parameter changes, changing skin textures and light colors, etc.).  But this is what I've learned so far.

I wasn't quite right about Scatter.  If you don't check "Use Material Color," it just seems to scatter white with a hint of the texture map.  I'm not at all clear on how the ratio of white to texture map is determined, but that's what seems to be happening.  It doesn't matter what Material preset the Scatter node has if Use Material Color is unchecked.  It always scatters the same.

If you do check Use Material Color, then it scatters according to the Material preset (Apple, Chicken1, Chicken2, etc.).  At least, this is what the manual says and what seems to happen at the end.  Looking at it mid-rendering, the scattering looks the same.  So confusing.

EZSkin2 uses scatter with Use Material Color unchecked.  If you check it, your results are more saturated and darker.  There doesn't seem to be a way to do this in the EZSkin2 interface,  but you can just do this by hand and use a material manager (like the currently free ShaderSpider) to propagate it throughout the different zones.

While Skin1 and Skin2 are based on light skin, they're both more saturated and darker than with Use Material Color off.  Even Marble is darker and more saturated than default.

While a multi-scatter solution has the potential to be more correct and address variations in scattering, checking "Use Material Color" might be a quick and easy fix for most people using EZSkin2 based shaders.

It would be nice to have a Scatter that had a slot for scatter color beyond the presets.  Scatter and Custom_Scatter simply don't work the same.  That said, you can do just fine with Custom_Scatter and other tricks.  I think I'm just about satisfied with my new skin shader, which uses a bit of both.



icandy265 ( ) posted Wed, 19 June 2013 at 4:45 AM · edited Wed, 19 June 2013 at 4:46 AM

@kobaltkween: Thank you, that's very imformative... I've tried using phong, specular and glossy... I even tried using ks_microfacet, which is OK but it mainly works (in my opinion) on eyes, teeth, etc... So I like to use Blinn, so what would be your suggestion in terms of skin specularity?

Also, yeah I've noticed that with HSV, it's very annoying... but in this case it worked, as long as I stay in the 0.000 - 1.500 range, anything higher than that seems to drive Poser crazy, lol. Would you mind pointing out how you get around that problem? Thanks...

As for the "Use Material Color" check-box, I figured that was what was happening, I just hasn't come up with a shader that has the check-box checked that looked natural yet, it always seems to be overly saturated... maybe I should try doing the double scatter thing, but one with "Use Material Color" checked and the other not checked? I will do a test render and let y'all know if that works... (one of) my motto(s) is "There's always room for imporvement" :)

@Eric Walters: Cool, good I'll probably stick to that site then... Yeah I wanted to see what would happen if I made the skin blue (inspired by you lol) so I tried, (a side note to kobaltkween, I ran into the very problem you mentioned with the hsv node, therefore I had to actually use photoshop to turn my skin texture blue, lol), and I also made a ambient-mask for her face to give her some cool "glow-in the dark" make-up. (Hasn't tested the actual "in the dark" theory yet though, lol).... Anyways this is what the shader I posted looks like with blue skin, lol. 

**EDIT: picture did not post will try again in next post sorry.
**


icandy265 ( ) posted Wed, 19 June 2013 at 4:46 AM

file_495338.png

Second try with picture...


Latexluv ( ) posted Wed, 19 June 2013 at 4:53 AM

I only understood part of what you were saying! :) But on one point, I think I understood you and it's what I've observed. The scatter node seems to take the textures (that I've spent a lot of time crafting), and lighten and brightens the crap out of them, altering the color that I intended when working in Paintshop. The whole current shader set up seems to be aimed at lightening and brightening the textures. This really drives me nuts! And the specular also drives me crazy. In many instances it makes characters look like they are oiled or sweating profusely. I'm looking for a 'dry' specular, if that makes any sense. I am avidly following this thread hoping to glean some ideas I can use. Thank you guys so much for dicussing this!

"A lonely climber walks a tightrope to where dreams are born and never die!" - Billy Thorpe, song: Edge of Madness, album: East of Eden's Gate

Weapons of choice:

Poser Pro 2012, SR2, Paintshop Pro 8

 

 


kobaltkween ( ) posted Wed, 19 June 2013 at 7:17 AM · edited Wed, 19 June 2013 at 7:19 AM

file_495348.jpg

Sorry, I don't think I was clear enough.  This is a problem with any type of specular node.  It was the conservation of energy trick I'm guessing you took from EZSkin.  Conservation of energy means your light can go either to specular _or_ SSS (or other types of shading, but those are the two you're using here), but not both.  The EZSkin CoE is a quick and dirty version of this that forces the specular into greyscale and doesn't include reflection.  Which works just fine pretty much all the time. I've never seen an image that looked like it used EZSkin and showed any of the problems I had with trying that trick.  But because I did encounter my own problems with that particular CoE trick, and they were weird and completely mystified me for ages, I thought I'd let you know about them in case you did run into the same problem.

But I wasn't talking about using Blinn specifically.  It's fine to use that if it works for you.  I personally just use a high intensity Specular or Glossy (if the material is shiny enough) with Fresnel controlling the intensity.  That way my reflection and specular take the same IOR based Fresnel control and I don't worry about trying to figure out the relationship between Eccentricity and IOR. But that's an ease of use issue.

I will say that I'm really curious about your intensity control on your Blinn.

To avoid using HSV, I mainly multiply by the color I want after saturation and value shifting.  I could do more complex things, like use the Photoshop layering equations (I've translated them into Matmatic and nodes), but for now that's overkill.  At least, that's how I handled dermal scattering.  Subdermal I do blend between the texture and the texture multiplied by a subdermal color, with a control based on the amount of red in the skin. 

I've done other tricks as well, like when I made a blue and purple hair material.  I combined HSV with colored swatches.  But I always use the same custom blonde texture in my hair materials, so I know the range my texture works within.

In terms of whether or not using the actual Skin 1 or Skin 2 materials are too saturated, I really think it depends on what you want as an outcome.  When I tested plain EZSkin2 (my SSS control) against plain old default (basically diffuse),  EZSkin2 with Use Material Color checked was tanner than default.  But it just looked like tan skin to me.  I don't find it unnaturally saturates the material.

Which is all I really care about.   I don't so much care about being true to the skin tone of the original texture.  Mainly because I don't have a huge library of V4 textures (I do of V3 textures, though, so I can't claim any frugality), and I have an even smaller number of "go to" textures.   I get a lot of my diversity from Photoshop and materials.   And since I figure a lot of people just don't want that milky look but don't want a lot of trouble, that could help a lot. 

Also, I just think it's good to have an option beyond white scattering.  That's why I went to Custom_Scatter in the first place.



icandy265 ( ) posted Wed, 19 June 2013 at 9:22 AM

file_495355.png

@kobaltkween: Oh okay... Well I haven't encountered any problems as of yet... I actually got the scatter + blinn plugged into blender plugged into color_math idea from a thread by bagginsbill, not from EZskin... I tried EZskin but I found it easier to read up on it and figure things out myself... I like to learn, lol. I'm far from perfect but concidering everytime I browse the forum I learn a new skill I think I'm getting there, lol...

Speaking of not knowing how to do things, I usually use edge_blend because I'm not sure how to properly use fresnel to control my blinn, could you possibly explain that process?

I tried the double scatter with scatter #1 having "Use Material Color" checked on and the hsv with the redder tint plugged into it, and scatter #2 without "Use Material Color" and the desaturated-yellow-tan plugged into it... The attached pic is how it turned out... I like it, but I think it depends on personal preference... I really don't think there's a right or wrong one in this case. Hehe

P.S: Just in case you can't tell the difference... This pic her skin is more pink in tone and has more scatter especially on the ears :)


kobaltkween ( ) posted Wed, 19 June 2013 at 10:18 AM

Oh, and I think I just figured out some GC color math issues.  If you use GC, when you do color adjustments of any kind, it throws them off.   For instance, if you take a 50% grey swatch and plug it into both slots of a color math node, you'll get a color less than white.  The solution is Gamma nodes.  If you want to adjust a color or image before putting it into a shader, you need a Gamma node with nothing checked for each color or image, and a Gamma node with invert checked after the final color adjustment and before shading.  That will make the adjustment work the same with GC on or off.

Latexluv - Not exactly on the Scatter node.  The Scatter node without Use_Material_Color checked seems to scatter white or close to it.  The Scatter node with Use_Material_Color checked seems to scatter the color of the Material preset you choose in the pulldown menu.  None of which is as customizable as Custom_Scatter, which lets you set surface, scatter, and pre-scatter (useful for a 2nd or 3rd layer of scattering) colors. 

For a quick and easy solution if you already use Scatter, try checking Use_Material_Color with different Material presets. 

In terms of specular, that completely depends on the shader you're using.  EZSkin2 gives you the option of controlling specular.   But the most simple solution is lowering the Reflectivity and raising the RollOff.



icandy265 ( ) posted Wed, 19 June 2013 at 11:01 AM · edited Wed, 19 June 2013 at 11:04 AM

I don't use GC... I use Poser 9 and (could be wrong) but I seem to recall that GC is only in the Pro versions? Even so my renders look good as they are and I would need to learn even more to make what I know compatible with GC...

@latexluv: I usually make the Eccentricity about 0.400000 and the SpecularRollOff about 0.200000, with a Reflectivity of between 0.600000 and 1.000000... Also with the lights it usually works to lower the "specular" to completely black on regular lights and have only one specular light with solid white... this way it minimizes the amount of shinyness the lights in the scene cause. If only one spec light is not enough then on the "Main" light, (the light that fills from the front) up the "specular" to a medium-to-dark grey which seems to be equivalent to making the spec value about 0.5 or so...

EDITED: to add a few more suggestions...


kobaltkween ( ) posted Wed, 19 June 2013 at 11:29 AM

Quote - I actually got the scatter + blinn plugged into blender plugged into color_math idea from a thread by bagginsbill, not from EZskin... I tried EZskin but I found it easier to read up on it and figure things out myself... I like to learn, lol. I'm far from perfect but concidering everytime I browse the forum I learn a new skill I think I'm getting there, lol...

Oh, you're doing great.  And Bagginsbill made EZSkin, so I wasn't thinking you were any less of a do-it-yourself person by deconstructing his material on your own.  He's written about the single channel problem, but that's going back a ways.  Years by now.  I know because I forgot he wrote that, started getting heavy into materials, had the problem, then remembered his comment about Blender having a single channel.   It hadn't made sense to me at the time because I was thinking of the swatches, not the Blending parameter.  And, like most people, when I thought of specular, I thought of white.  Duh on me.

The more correct method would to use Color Math on Subtract instead of Blender, with a Color Math on Clamp after that and before the Color Math add.   But more correct at that level probably isn't important.

If you want to test for the issue (which is far from necessary), color your lights.  You might try the typical pure orange and pure cyan.  If it renders fine, then don't worry.  If it doesn't, well, your lights always need to be white to use that shader.

Quote - Speaking of not knowing how to do things, I usually use edge_blend because I'm not sure how to properly use fresnel to control my blinn, could you possibly explain that process?

You can't control Blinn with a Fresnel node accurately.  Blinn already has Fresnel built into it.  In your shader, you're actually going against Fresnel with that EdgeBlend that has a dark outside and light inside. A more slightly accurate Blinn would use an Eccentricty of whatever matches the IOR (index of refraction) you want.  I know higher IOR (shinier) means lower Eccentricity, but honestly, I have no clue after that.  Same goes for the SpecularRollOff.  I've created relationships that bring down rolloff as IOR goes up, but I can't say they're accurate.

Working with the intensity and rolloff of blur are essentially coming up with what the built in lights would look like if they were actually real and were blurrily reflected in your surface.   How big is that imaginary light mesh?  How far away is it?  I find it really hard to judge.

Now I work with emitting meshes in addition to lights, and depend more on reflection than specular.

You don't really have a use for Fresnel in your shader as it is, but if you added a Reflect node with high blur, you could control the Reflection value with a Fresnel_Blend node.  You just set the Outer_Color to white, Inner_Color to black, and give it the IOR you want.



icandy265 ( ) posted Thu, 20 June 2013 at 1:57 AM

This just goes to show what I thought I knew, I do not know, lol... I didn't know that Blinn had built-in fresnel, so I will get rid of the edge_blend and I guess just not plug anything into Reflectivity? Lol...

I will test the colored light theory, what should I look for, in terms of things that wouldn't look right if the shader was incorrect?...

Also, don't mean to sound a little dumb (lol), but how do I determine IOR in reflections and such... I usually keep it at it's default cause I'm clueless and don't want to ruin anything... Also how would I determine what specular settings match the IOR?

I hope I'm not asking too many questions... sorry.


kobaltkween ( ) posted Thu, 20 June 2013 at 4:52 PM

Quote - I don't use GC... I use Poser 9 and (could be wrong) but I seem to recall that GC is only in the Pro versions? Even so my renders look good as they are and I would need to learn even more to make what I know compatible with GC...

Oh, I wasn't posting that for you specifically.  I was just sharing information for people who do use GC.  For instance, IIRC, Eric Walters uses it.    I figure lurkers or searchers stumbling across this thread might find it useful.

You're correct about GC being a Pro feature.  Or at least you were correct.  The new P10 has GC, which I think is really good.  The only difference between this version's regular and Pro software seems to be content creation tools.  I think that's a fairer distinction.  I don't think everyone "should" use GC, but I do think all Poser users should have the option.

In my experience, the only time switching to GC is hard is when your materials or lights try to compensate for the problems of regular workflow on their own. 

I started using GC in materials after reading Bagginsbill's posts on it.  I never had a transition problem, because I always tried to match my properties to real world ones.

I don't see anything in your material that would be a problem in a linear workflow.  If most of your materials are like that, it should be smooth sailing to try it out some day. 

Quote - Also with the lights it usually works to lower the "specular" to completely black on regular lights and have only one specular light with solid white... this way it minimizes the amount of shinyness the lights in the scene cause. If only one spec light is not enough then on the "Main" light, (the light that fills from the front) up the "specular" to a medium-to-dark grey which seems to be equivalent to making the spec value about 0.5 or so...

Those lighting techniques might be a problem if you ever use GC, but only because they're physically inaccurate even without GC.  Real lights always cast shadows and surfaces always reflect (more or less, depending on the surface) what lights emit.  When you start messing with light properties beyond color, intensity, and falloff, you're moving outside of what's physically possible.  Which can be fun and artistically rewarding, but isn't necessary for realism unless there's another technical problem.

If you're finding you need to boost your lights on your diffuse without boosting your specular, that might be because you don't use GC. 

I switched to linear workflow because even material GC gave me more consistently accurate results than regular worklfow.  It made my life much easier.

The only reason I'm going on about this is that you've said you're beginning to explore materials.  When you don't use GC, it's harder to learn to make more complex materials.  You lose chunks of your gamut, all your calculations are wrong, and your bounced light is more inaccurate with each bounce.  It's a lot to work around.

If you've already built most of your work-around, if you're 99% of the way to where you want to go with materials and lights, then awesome.  Just pick up a tip or technique here or there and enjoy.   But if you're significantly further from your goal than that,  your journey will be much harder without GC.  The more calculations you add to your material, the more you have to compensate for.  Even if you're happy with your present work- and I can see why you would be- your present workflow could make reaching your future goals more difficult.  Depending on what they are, of course.

I tend to think of it as a translation issue.  It's like the monitor speaks Italian, the images are in Italian, but the renderer only speaks Spanish.  Similar, but not identical languages.  Considering our own language, the real world or the world we imagine, to be English (or some other totally non-Latin language, take your pick), making a render is like trying to take something you've written in English and converting to Italian working with those two people who only speak their own languages. 

Regular workflow has the Italian interpretting the Spanish like it's Italian, the Spanish speaker interpretting the Italian like it's Spanish, and you speaking a pidgin to try to bridge the gap between the two.   Not hard for simpler texts, but very hard for highly nuanced and complex communications.  Linear workflow, or GC, gives you a translator to go between them.  You still have to understand those two languages yourself, but you no longer need to fight the misunderstandings between them.

If you already built a hybrid, pidgin vocabulary and became fluent in it, then it's probably not worth going back to simple sentences just to avoid some consistent grammatical errors.   But if you haven't, building that pidgin vocabulary is a lot harder and more limiting than not having to.



kobaltkween ( ) posted Thu, 20 June 2013 at 4:53 PM · edited Thu, 20 June 2013 at 4:57 PM

file_495398.jpg

> Quote - This just goes to show what I thought I knew, I do not know, lol... I didn't know that Blinn had built-in fresnel, so I will get rid of the edge_blend and I guess just not plug anything into Reflectivity? Lol...

You have nothing to be ashamed of.  I only found out Eccentricity was a form of inverted IOR when I was reading on the web at some point well after using Blinn for years.

If your shininess is even throughout the material, then yes, just leave your Blinn alone.  If it isn't, if you have a specular map, then where the map is brighter and the material shinier, you want a lower Eccentricity, lower SpecularRollOff, and higher Reflectivity.

To use your specular map with Blinn, you need to define a mathematical relationship between "shine" and each of those three Blinn properties.  You have to define what a "shine" of 1 looks like, what a "shine" of 0 looks like, and the transition between them for each property.

I initially just followed Bagginsbill's equations for those three "shine" relationships (you can find them here in the forums).  Going beyond them to something that better suited my work was time consuming.

To make my life simpler, I now mostly use a specular node without Fresnel built in (i.e., one that doesn't get brighter at the edges), plug the Fresnel into its Reflectivity, make a Math Add node with a base number of at least 1 and a second number to add up to I want the highest IOR to be (for instance, Math Add (1.1, 0.15)), then plug the specular map into the second value.

It sounds more complex than it is. ;D

I built a relationship between IOR and RollOff, but since that's basically how big and blurry a fake reflection of a non-existent light mesh should be, I've gotten really loose about it recently.

Quote - I will test the colored light theory, what should I look for, in terms of things that wouldn't look right if the shader was incorrect?...

You'd be judging your specular colors.  If you want a control to compare it to, you can use the more accurate node set up as shown in my attached image.  Just use Blinn instead of the Specular node I used, and don't involve the Fresnel Blend.

It's not exactly a theory.  It's math.  The conservation of energy solution you've used is incorrect.  That's a fact, not something you need to test.  What you'd really be testing is - Can you see the error?

  • If you can see it, is the difference significant?
  • If it is a significant difference, is it worth time and energy you could spend elsewhere?

To make the problem you're trying to spot more concrete, here's the math. I've broken the equations out into each color component.  First the correct equation for those two elements:
Red Final = Clamp (Red SSS - Red Blinn) + Red Blinn
Green Final = Clamp(Green Final - Green Blinn) + Green Blinn
Blue Final = Clamp(Blue SSS - Blue Blinn) + Blue Blinn

Clamp means any results above 1 get converted to 1 and any below 0 get converted to 0.  Blender's Blending input does this automatically.  So this is the equation you're using:
Blinn Grey = (Red Blinn + Green Blinn + Blue Blinn) / 3
Red Final = Clamp (Red SSS - Grey Blinn) + Red Blinn
Green Final = Clamp(Green Final - Grey Blinn) + Green Blinn
Blue Final = Clamp(Blue SSS - Grey Blinn) + Blue Blinn

Let's say a particular spot on surface has SSS shading with an RGB value of (100, 150, 50).   And that the same particular spot has a  Blinn value of (50, 175, 100).

The first equation becomes:

Red Final = Clamp (100 - 50) + 50= 50 + 50= 100
Green Final = Clamp (150 - 175) + 175 = 0 + 175 = 175
Blue Final = Clamp(50 - 100) + 100 = 0 + 100 = 100

So the correct final color is (100, 175, 100).

The second equation becomes:

Blinn Grey = (50 + 175 + 100) /3 = 108 (rounding to the nearest 1, as colors do)
Red Final = Clamp (100 - 108) + 50 = 0 + 50 = 50
Green Final = Clamp(150 - 108) + 175 = 42 + 175 = 217
Blue Final = Clamp (50 - 108) + 100 = 0 + 100 = 100

In your equation the final color is (50, 217, 100).  A much more green, and much less red color than (100, 175, 100).  In other words, your specular will have more of the light color and less of its inverse than it should.

All that said, if it looks fine to you, don't worry about it.   Rendering is just math.  You can do the math and calculate the difference between wrong and right equations.  Or even between more and less accurate ones.  But you need to use your eyes to judge whether that difference is worth bothering about.

Bagginsbill has a full and highly accurate conservation of energy system written out in Matmatic for dealing with all the different shading components, including reflection.  But he didn't use it in your reference or his EZSkin shader.  I haven't seen him say why, but I'd bet it's because he didn't think the difference was noticeable enough to be worth the trouble.

Judgement is the heart of testing lighting and materials.  It can be a fact that certain shading problems exist.  It can be a fact that certain people can see them.  Those facts don't mean you have to change what you're doing.  Only you can decide if those issues are important.

Regular workflow is inaccurate.  I can often spot the problems of regular workflow in people's renders.  Does that mean those aren't good or even great works? Not even by my own standards.  I've favorited thousands of works with regular workflow problems I could see.  The same goes for the myriads of different technical issues I've seen in works, from anatomy to gravitational effects to basic composition rules.   None of those issues stopped the works from having an impact on me.

A highly positive critique can include several technically valid and artistically relevant flaws as long as the merits outweigh the flaws.  Every choice an artist makes has a cost as well as a benefit.  Only the artist can decide what choices are worth the cost, and what strengths are most important.  And, for that matter, which critiques are helpful and which aren't.

Quote - Also, don't mean to sound a little dumb (lol), but how do I determine IOR in reflections and such... I usually keep it at it's default cause I'm clueless and don't want to ruin anything... Also how would I determine what specular settings match the IOR?

You definitely do not sound dumb.

IOR is kind of easy because scientists have done the work of measuring lots of values.  You can find charts and lists of IOR values online.  Water is 1.33.  Corneas are about 1.38.  Glass is around 1.54, but varies based on the type of glass.  Diamond is 2.4.

Even though you'll find metal IORs as low as 1.44, that's incorrectly ignoring the imaginary component.  I find metals work best with an IOR of about 15 to 20.

I use those as my basic scale.  A car won't be shinier than a diamond, but it can be shinier than glass.  A regular wet surface will probably have an IOR somewhere around water's.    I tend to keep regular skin around 1.25, but someone like Latexluv might want to get closer to 1.1 or lower.  Checking, vegetable oil is 1.47, which is probably the very highest I'd ever make skin or lipstick.

Just make sure you never let your IOR dip below 1.  1 is a pure vacuum, and lower than one requires a very special physical case.

And you're definitely not asking too many questions. ;D



icandy265 ( ) posted Thu, 20 June 2013 at 8:17 PM

P9SSS_SkinA-01 photo P9SSSV4iMR1_Skin2-0002_zpsfc7c073b.png 

P9SSS_SkinB-01 photo P9SSSV4iMR1_Skin3-0001_zps0ef9b61f.png 

These are the differences... The first one is the original shader, the second is the one you posted. I like the second one, but I was wondering why her ear and eye creases have white stuff on them? Don't know if you can see it or not...

Gonna try some other stuff that you got me thinking about while I was reading your previous post, so I'll post the results later tonight...

Also I noticed that even though I colored the lights (btw none of the lights have black for the spec anymore, I upped them all and colored those as well to test the skin) they don't seem to really "color" her, lol... If that makes any sense...

One other thing, I was looking in your gallery and I saw the one with the girl as half statue and half human reaching for the apple, (I love that btw), but how on earth do you get the lighting to look so good? I can never get anything like that and my shaders are always too light and soft and if I leave them sharp they look bad... Lol


kobaltkween ( ) posted Sun, 23 June 2013 at 11:50 AM · edited Sun, 23 June 2013 at 11:54 AM

Sorry this reply has taken so long.  I managed to lose the first version of it and had to rewrite it.

Hmmmmmmmm.  Yes, I do see the white spots, and no I don't know what's causing it.  It looks like very small and bright specular, but that equation should never give you specular that small.

I'm also stumped by your light color issues.  I never mess with diffuse or specular colors on lights, so mine are always default white.  I just color the light.  I would expect your lights to get nice and saturated by this.  

I made that image ages ago (Poser 6, IIRC), so I don't exactly use the same techniques now.  That said, the basic principles of my lighting have been pretty constant.  

I always start with a notion of what's happening in my scene, both on and off camera.  I make my lights match the real world scene in my head as much as I can.  This currently means using raytraced shadows.  I use a blur from 1 to 15 or so depending on what type of light I'm making.  My shadow bias is as low as I can get away with. I usually start with 0.2 and see how it goes.  My shadow samples are always higher than 32.  I've gone as high as 128, and I usually use 64. For spots I might use inverse square or linear falloff, and for points I use inverse squared falloff.

For environment lighting, I use IBL or an environment mesh with an emiting material.  If I use an IBL, I have to come up with a way to add the IBL's image to reflections.  If I use an environment mesh, I often have to come up with a way for something else to show in the background, because such a tiny portion of it shows that even a 5000+ px texture for the whole mesh isn't large enough to render well.  If I'm using the environment mesh to give windows or doors or other portals light, then I might boost the ambient value up higher than 1.  

As far as I can tell, the whole "fill" light element of 3 pt lighting comes from before GI and IBL.   I remember the old 3 point light tutorials, and the fill light always imitated bounced or indirect light.  I never use a directional "fill" light.  And I've always tried to match my environment lighting to my scene.

My directional lighting depends on my type of scene.

If it's an indoor studio scene, I usually have a main and accent light, though I might just use a main light.  I used to use spots for those, but now I use my own custom softboxes.  They're a combination of emitting props and point lights that I use as one light.  I'll eventually sell them as part of my photo studio set, but I'll need to stop using it and get back to packaging it.

If it's a candid indoor or outdoor night scene, then I light to match the elements of the scene that emit light.  I use single point lights for lamps, torches, candles, and glowing single glowing objects.  I use more than one for fires and large or long glowing objects.  The softer the light the source should cast (basically, the more diffused the light is), the greater the blur I put on the light.

For natural light, I always use a single infinite with very low blur.  Moonlight is hugely less bright than sun, and sunlight is strongest in the yellow spectrum.

The only really tricky thing I've learned is to watch what point lights are close to.  They seem to have a bug that gives them a weird hard shadow on anything that comes too close.



AetherDream ( ) posted Tue, 25 June 2013 at 10:26 PM

Well one thing I can say is that as far as really good resources/ multiple shot nude photos of the same person tend to be much more accessable for caucasians. I find one ethnic fully nude set of body and face shots for every ethnic one.  The lack of these photos might be one reason for the reduced number of 3D model textures and merchant resources that are ethnic.

"People who attempt define what art is or is not, are not artists"---Luminescence


stewer ( ) posted Tue, 25 June 2013 at 11:53 PM

Quote - Sorry, I don't think I was clear enough.  This is a problem with any type of specular node.  It was the conservation of energy trick I'm guessing you took from EZSkin.  Conservation of energy means your light can go either to specular or SSS (or other types of shading, but those are the two you're using here), but not both.  The EZSkin CoE is a quick and dirty version of this that forces the specular into greyscale and doesn't include reflection.  Which works just fine pretty much all the time.

Note that the trick in EZSkin is not providing conservation of energy (even though it is intended to). It is using the output of one lighting node to change the attenuation of another one, which is not how real surfaces behave. Skin doesn't change its specularity based on how much light you shine on it, and it especially does not change the amount of diffuse or scattered light it reflects from light source A based on the angle of light source B.


kobaltkween ( ) posted Wed, 26 June 2013 at 12:17 PM

Quote - Note that the trick in EZSkin is not providing conservation of energy (even though it is intended to). It is using the output of one lighting node to change the attenuation of another one, which is not how real surfaces behave. Skin doesn't change its specularity based on how much light you shine on it, and it especially does not change the amount of diffuse or scattered light it reflects from light source A based on the angle of light source B.

But the EZSkin CoE isn't working on attenuation?  The only thing that affects the EZSkin specular is either a real or an auto-generated specular map.  If you mean icandy265's Edge Blend, which also has a generated specular map fed into it, that's not CoE.  The equations I posted are exactly how the CoE is handled.  No attenuation or angle involved.



stewer ( ) posted Thu, 27 June 2013 at 2:42 AM · edited Thu, 27 June 2013 at 2:47 AM

Attached Link: http://www.rorydriscoll.com/2009/01/25/energy-conservation-in-games/

Subtracting specular from diffuse isn't correct either. Conservation of energy must happen over the entire hemisphere that light can be reflected, not just one viewpoint:

Consider a perfectly diffuse surface with a color of (1,1,1). The total amount of light it reflects is (π, π, π) - the integral of (1,1,1) over a hemisphere. Now imagine the same being a perfectly specular surface, how should that reflect? It would reflect (π,π,π) in exactly one direction and (0,0,0) in all the other directions. Thus, clamping the output of lighting nodes to (1,1,1) is losing energy, and that's not even counting light sources with an intensity > 1.

Conservation of energy in a shader is about making sure that the total amount of light reflected in all directions does not exceed the light the surface received. Any math based on the output of a ligthing node is only taking one direction in account, not all of them. Your equations still let the diffuse reflection of light A be affected by the specular reflection of light B by subtracint all specular from all diffuse.

To turn a shader that's not conserving energy, such as the simple phong specular, into a shader that is conserving energy, you have to normalize it based on the specular exponent. See the attached link for an explanation.

You are right though, in the end what counts is how it looks when rendered, not how it looks on paper.


kobaltkween ( ) posted Thu, 27 June 2013 at 1:46 PM · edited Thu, 27 June 2013 at 1:57 PM

It's not clamping the specular.  It's clamping diffuse - specular.  And the diffuse is just as combined as the specular.   Even splitting the equation into lights wouldn't make it incorrect. 

(DiffA + DiffB + DiffC + .... DiffN) - (SpecA + SpecB + SpecC + ... SpecN) = DiffA - SpecA + DiffB - DiffB + DiffC - SpecC + ... DiffN - SpecN

sure you could just as accurately express it as

DiffA - SpecN + DiffB - SpecN-1.... DiffN - SpecA, but that doesn't change the equivalence nor have a real purpose.

Look at the equations I posted.  Specular can still go over 1 (or 255, depending on how you're describing the color).  The clamping just prevents the subtraction from going below 0, and creating a negative diffuse color where the specular is brighter than 1.  Or, thinking about it physically, it says that a very bright light doesn't spontaneously create anti-photons. ;D  Besides, it seems to me that without the clamping, the equation is purely Diffuse - Specular + Specular = Diffuse, and there's no point in having the specular at all.  Which wouldn't make any sense.

As for your information about normalization, I can sort of see your point with that.   I only say sort of because I'm not at all versed in the different diffuse and lighting models and their equations, nor do the examples on that site look like any of the tests I've ever done over the years.  I've done the whole sphere test thing, and never seen the reduction in specular intensity he demonstrated, so I've got no experience to relate his findings to.  I have noticed that Specular, all on its own, seems to (unnaturally) get brighter with higher rolloff.   But that has nothing to do with CoE in the material (I can't say anything about the node itself).   Also, he doesn't seem to be taking into account the Fresnel effect at all, which I'd have expected to be an issue in realistic specular.  In other words, I definitely take your (and his) word for what you're talking about, and I can sort of see what the math is saying.   But I don't have any theoretical or experimental experience to relate it to.

That said, I'm just not that fussed about the fudged reflection of a light that doesn't actually exist.  I've never seen results that in any way, shape, or form implied a solid and unchanging relationship among specular reflectivity, light intensity, real world lights, and real world reflections.   As I mentioned, changing the rolloff on Specular while keeping the value constant makes it look like the effect from a brighter light, rather than the more diffused and blurred reflection of the same light source.  Just looking at Blinn, I've got no clue at all what the equation is for getting Eccentricity to match up with IOR, even though Eccentricity controls Fresnel effect strength and must therefore have some relationship to IOR.  For me, getting specular to look right without emitting meshes has always been a strange exercise in imagining real lights, then imagining their reflections, then trying to imagine their reflections blurred on a given surface. 

Which I think gets to my larger concern about CoE.  I tend to use emitting meshes and reflections in addition to specular.  I think of specular more like a special effect than a realistic element, so the real accuracy usually involves reflection.  Whenever I've tried to include reflection in CoE in my own shaders, I've gotten some pretty wacky effects in my reflections at times.  Like reflections in negative colors but positive shading (that one really threw me).  Or just plain crazy colored artifacts all over everything.  I've even tried inverting Fresnel on the diffuse amount, but that just made black edges that didn't look correct or good.   I now do pretty much what EZSkin does: control the reflection amount with Fresnel and leave it at that.   Nothing else has worked as consistently or as accurately. 

If I'm not going to use CoE on reflection, using it on specular seems moot.  So most recently, I personally don't tend to apply anything but Fresnel to reflection and specular.  It's been working for me pretty well so far.

To be very honest, CoE is at the absolute bottom of my list of material and rendering difficulties.  I've seen some significant errors with addition of elements in the root node using GC.  I've had really weird shading errors with surfaces that get too close to point lights (mainly a black circle of shadow), which is a problem for lamps that I want to cast proper shadows.  Errors which vanish if I go pure raytracing by forcing everything through refraction, but that makes the whole light work differently and the render take longer.  I get serious blotches all over certain meshes (like ones with fine details, like vents) due to IDL occlusion problems, even with samples up to 10,000 and shading rates down to practically nothing.  Every now and then, I get black spots all over my reflective surfaces.  Spots which go away if I start with new clean scene and rebuild to exactly the same scene.  I was recently doing some hair tests, and getting huge, bizarre occlusion-like blotches in what seem to be random places underneath transparent mesh.  Since I've had this happen with other people's shaders and meshes in the same very simple test scene, I can't say it's just my mistake.  I'm sure I could make my diffuse/SSS and specular/reflection combinations more accurate than they are, but frankly, that's not where I'm taking major hits to realism, let alone experiencing the biggest rendering errors.

To be clear, I'm not complaining.  I usually don't have to fight to get good results.   Those are just my current concerns.



kobaltkween ( ) posted Thu, 27 June 2013 at 4:13 PM

Quote - Well one thing I can say is that as far as really good resources/ multiple shot nude photos of the same person tend to be much more accessable for caucasians. I find one ethnic fully nude set of body and face shots for every ethnic one.  The lack of these photos might be one reason for the reduced number of 3D model textures and merchant resources that are ethnic.

That's a very fair point.  But most of us can't do anything about photo resources.  Most of us can, however, make materials that work with darker textures, fix hue and saturation problems in Photoshop, correct burned in artifacts, and eliminate texture features that don't fit the intended ethnicity very well.  There's no dearth of free online references for most ethnicities.  One or two good photos and some time in Photoshop and the material room can help correct a lot of problems.



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