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  05 May 2013
hmm. no, still not there... let me help you out.

the best way to setup skin shader is imho this - put a single strong light source in your scene.
and try to achieve this:

the reddish soft looking bleed in your core and cast shadows.

which you are definitely not achieving in your shader right now. yours still look kinda like a basic hard blin surface (the eyes too). looking at your wrinkles, theyre still not looking like a soft translucent material. and the redness i see in your nose is just a tinted occlusion right?

so my advice is, ignore your texturing for a moment and try to get the shader right first.

good luck
  05 May 2013
Yeah, you are right. The weird thing is that when I tried to do what you said, I get a strange result. no matter how much I change conversion factor, back scatter weight, radius, or depth, i don't get that reddish color you say, specially beneath the nose. here is what it is like:
  05 May 2013
youre using mental ray or vray?
if mental ray, whats your sss shader, the old one or the new one ?
  05 May 2013
Mental ray. Is there a new one out there? I use the default shader.
  05 May 2013
well, now we identified the problem. (yes there is a new mr sss shader :http://forums.cgsociety.org/showthread.php?t=1052423)
the standart mental ray sss shader is imho pretty crappy, it cant simulate the color bleeding needed for realistic skin rendering on its own , thats why the skin in your renders looks so flat.

i encourage you to read through this thread :

or switch to a different renderer, like arnold or vray.

Last edited by kybel : 05 May 2013 at 06:31 PM.
  05 May 2013
I read through 19 pages of the link. really great stuff and helpful tips they discussed, I got tony's shader but I dont know how to work with it. here is what it looks like as default. do you know how to set it. because by default it does not have,reflection,spec or even backscatter weight.
  05 May 2013
well then time for some research, testing and learning i guess
i can see theres a front and back scatter, both have color radius depth and weight attributes
but yea. this is maybe a too advanced shader for non-experienced user.

so if thats a problem maybe you can try the new mental ray sss2 shader. you have it if youre using 2013 version (or above) of 3DSMax. its just hidden (check this thread. http://forums.cgsociety.org/showthread.php?t=1068321)

either way, youll have to abandon the default shader as soon as possible, cause youll never get a good realistic looking skin renders with it. and from what ive seen , the mental ray sss2 looks really robust, almost as good as the vray skin shader, definetly capable of some great results.

so good luck to you then, keep your head up and your spirits high

Last edited by kybel : 05 May 2013 at 12:02 PM.
  05 May 2013
Because I have heard so many people complimenting about vray sss 2, so I thought why not give it a shot. I tested it on a head model I did some time ago. I had rendered that in mentalray and now in vray. but theres another problem with vray. It does not cast hair shadows which is really important. I searched through the net for a solution, some said it should be changed to geometry, some sadi in mr prim. but the problem is that one time you open max and render hair. there it is, the hair and shadow, another time you open the same file but it does not cast shadow or even the hair itself. I realy dont now what to do. altough it has a really cool sss shader to work with, but hair is really important for me. below is the test of Vray and Mr of the same model. there is no hair shadow in vray as i said.
  05 May 2013
i dont know whats your hair solution, so i cant help you with this.. (though you could render a shadow pass in mr and comp it later, but thats a pain in the arse)

im just saying that shader-wise the default mr sss shader is sadly the worst out there today.
on one hand im a fan of vray, but i also use a hair system compatible with vray (+vray has a top class hair shader), hair really is important.

so if i were in your shoes, i would go for the misss_fast_skin2 which is in terms of quality on par with the vray skin shader, and could be also compatible with your hair, since its still a mr shader
  05 May 2013
I unhided the sss 2 and used it. here is the test. it lookes better but still not getting that reddish color in your image. the setting of backscatter is shown below. would you help me to figure it out. I would appreciate alot.
  05 May 2013
I worked a little more on SSS2 and it got lot better. I think its time to get back to Gollum now that the skin is working. heres a test:
  05 May 2013
youre on the right track i think. you have a shader capable of realistic results, now its just a matter of getting grip of it, you see, its not something youll get right in a day or two, youll have to do a lot of tests so you understand what each parameter does, and how it affects the overall look of the shader.

so to your renders. once again, turn off your textures, reflections and also gi, you dont need none of that when setting the sss, stuff like gi can only mislead you

i for once never used that shader so i dont know exactly which parameter does what, but looking at your shader, i can tell that the problem now is that the scattering is reaching too deep into the skin, it needs to be much much tighter. i would play with the radius parameters to achieve this.

also when you look at your bump details, they look wery harsh, not very skin like, adjusting the radii could also solve this problem. for that to happen however youll need to bump up the sss quality, in vray its done with the prepass rate, but thats not the case in mr, in mr i think youll have to bump up the light map resolution or something like that, but since i never used that shader i could be also wrong.

i did a render to show you what im talking about :

its all a bit noisy but i just wanted to render this quickly.
but notice how the various skin pores, dimples, lip wrinkles...etc look much softer in the core shadow on the left. you can also see the red bleeding effect there as well.
you can also help this with a trick i came up with in photoshop - blurring only the red channel a bit

thats about it, dont feel like im bossing you around here , im just saying how i would have tackle this myself, doesnt mean you have to do it exactly that way, in the end its entirely your call, keep it up

Last edited by kybel : 05 May 2013 at 01:30 PM.
  05 May 2013
Thanks man, I appreciate your help. I guess I have to work more on my shader. because the one you uploaded is much more lifelike, Dam it! skin shading is really time consuming and difficult in mr. I am also working in vray to have a comparison with mr SSS 2. got to tell you that looks better than my mr SSS 2. once I get the result I m looking for I will post a side by side image and then to decide which engine to work on.
  05 May 2013
cool , should be interesting to see it side by side
  05 May 2013
Hey guys, I have prepared a side by side image to compare my Mr SSS 2 and Vray SSS 2. I should add some information before that. I don't know if you too have the same problem or not. Vray decreases the normal map details drastically while it's really cool with displacement map, on the contrary Mr is great with normals but not that good with displacement. so in this image you see the fine details are more visible in Mr render. another think is about specular,reflection and glossiness. in vray when i add spec map to spec color or spec weight, spec vanishes completely as if the skin is a object with zero amount of specularity, so i just used gloss map in spec glossiness, but in mr, because we have a pallet for spec,another one for reflection and a separate one for glossiness i had more control over specularity of the skin, I don't know how to deal with it in Vray. Another think is render time, it took about 40 minutes in Vray but in Mr it took just 15 minutes. considering these things and more importantly the quality of the render, which engine do you think should i go with for this project?

Last edited by HosseinDiba : 05 May 2013 at 09:25 AM.
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