[DT3D] UDK Skin Shader

[migusan76]

DT3D UDK skin shader is a real-time multi-layered skin model implementation in the Unreal 3.x Engine. The shader is based on research from “Efficient Rendering of Human Skin,” implementing most of the effects described in the paper including the multi-layered diffusion scattering in skin. Along with the multi-layered subsurface scattering the shader implements the physically based specular term to better capture the specularity of skin. This is a great shader for the artist that wants to push there characters to that next level. Also can be quite usefull for those artist using the UDK for pre-vis work.

[Piranhi]

Wow, it looks very nice!

[KazeoHin]

Fantastic work! I'm a lover of UT3 shaders as well, and I love to see others fully taking advantage of the engine's material editor! I hope this shader is truly appreciated as it deserves to be.

[eAlex79]

This shader looks really good.

And your Logo looks like something I've seen before.... Something from Mars if I remeber right...

[migusan76]

Thx's Piranhi, eAlex79. lol yes how did you know it was from mars...

KazeoHin I totally agree, I truly love the material editor in ue3. I think its the best by far in my opinion. Gives you a nice blend of shading nodes with a mix of visual programming.

[Geona]

why is there skin on the hair?

[KazeoHin]

And your Logo looks like something I've seen before.... Something from Mars if I remeber right...

Well, you may be able to remember where it's from. Maybe you have to open your mind

[migusan76]

Geona - the idea is for hair to be on hair planes and not in the manner that I showed in this example. Also the material can be tweaked so you can bring in a mask for hair and other sorts of things like that if this style of hair is your way of going.

KazeoHin - Yes now I remeber, quaiD... QUIAD....

[eAlex79]

The resemblence is daunting, isn't it?

[Shelke]

Absolutly amazing! Thanks for posting .

[danimal']

While I don't dispute the awesomness of that shader network (good lord!), my uneducated initial opinion was that there's too much specular and the skin looks rather waxy? Rendering is one of my worst subjects, so if I just don't know what I should be seeing ignore me, it's definitely cool that you did this Just my impression. Here's a comparison for what I personally like (again I'm really noobie in terms of rendering knowledge), this guy achieved this in UE3 with spherical environment mapping to achieve that subsurface scattering effect (and there's no noticeable specular):

[eAlex79]

Yes that looks good too right? I played with it, and I tried to remake shaders ZBrush uses f.e., but they don't ever come nowhere near good looking (the sides of the sphere are badly mapped nomatter what is there on color information).

Probably one needs to use a flat(er) texture and combine it with other mappings.

[migusan76]

Shelke - thx's!

danimal - no biggie, I would agree that maybe my hand slipped on the spec there making it look slightly waxy. The nice thing about a shader is it can be tweaked and if you're not a fan of the spec, you can knock it down. I've seen that example before and by no means does it achieve anything close to skin rendering in my opinion. The spherical environment mapping is a nice parlor trick that can achieve cool results when it comes to highly reflective metal materials or high blur diffuse objects. Here is an example of a side by side comparison showing your traditional Lambert shading and the custom skin shader. Also a pure white light break down so you can see the color bleeding better. Hope this helps push my point a little more, but if it doesn't then eAlex79 will agree "Openn urrrr mind quaiD" Opennnn urr Mind"

[danimal']

Yes that looks WAAAAAY better IMO. It's that "initial response" issue with page 1 where my eye/brain just doesn't accept that what it's seeing is skin, but the above tweaking goes right past my eye/brain's "do I accept this as skin?" test Default looks frankly a lot more like the page 1 post, the tweaked Multi-Layered example above is much, much more realistic. Really cool stuff.

[migusan76]

well I updated the first page post to reflect a better lighting situation so it shows it off better.

[dennydenning]

Very nice. I am still educating myself with the material editor. So, nice to have references to study. Thank you.

[Reality4]

Hi migusan76,

Really, really, REALLY great work. I have the original book by nVidia (GPUGems 3), and for me it's really difficult stuff. I've been trying to get sss going inside the UDK, but with little success.

So thank you so much for 'converting'/adapting this technique to the UDK. The scattering is beautiful!

Charles

[migusan76]

thanks Charles and Denny! Really glad to hear this Is helping out.

[JohNLA]

Finally found some time to play your shader and it is really fantastic work. Still images do not do it justice.
I still very new to creating Unreal shaders so excuse my ignorance but I can not find where get access to the Common Material Attribute Information as shown in your instructions.

[migusan76]

Hi JohnLA, No problem. I guess I should have stated it in the instructions, but normally if you right click the material and make an instance of it you can get the shader parameters and tweak that way.

[JohNLA]

Bravo, all works great now

[tyrone70]

Whoa! That's Awesome! How do people even begin to figure out their own custom lighting materials is beyond me.

[Reality4]

Hi migusan76,

I'm running into an issue with your shader.

Everything works fine in the material editor.. But as soon as I add a model to a scene the scattering disappears, and after I hit 'Build All', the normal maps don't work anymore, and I only see a smooth surface with the diffuse map, no scattering or other effects.

Any idea what would cause this?

Thanks!
Charles

[eAlex79]

Static lit static meshes don't look that good.. put it on a Skeletal Mesh or something that moves around and is dynamically lit

[Reality4]

Ooops, yes of course Thanks eAlex79. And wow... the shader even looks a lot better now with the scene lighting!

[JohNLA]

I also noticed that he sets his textures to be saved as TEXTUREGROUP_Skybox textures instead of TEXTUREGROUP_Character and that allows for 2048 textures and does not downsize them to 1024

[eAlex79]

If you setup your ini's right you don't have to put your texture to the wrong group

[Mandinga]

Superb, this exactly what characters should be pushed to.

[Reality4]

Hi migusan76,

Another question on your shader. In the nVidia Human Head demo there is a parameter called "waxy".

I would like to use such a parameter to increase or even exaggerate the scattering effect, also to create non-human skin effects.

I tried to find such control in your shader by tweaking it, but since I don't really understand what's happening under the hood I failed in achieving this.

Could you tell me what I should change to create a similar parameter?

Thanks,
Charles

[migusan76]

Hi Charles,
There should be a way to control the density of the material, by simply multiplying the top diffuse layer and the normalizing table, but this would only decrease the scattering effect. The nvidia is a little more complex since its running the diffusion blurs in real-time in texture space. So that waxy attribute is probally some sort of factor to increase the gaussian blurs which in essense increase the blur radius and the scattering effect. Not sure that can be done in UDK and it be running efficient.

[Reality4]

Okay, thanks migusan76. I also tried different blur values, but that didn't really make it more waxy.

I guess you heard about ShaderFX (http://www.lumonix.net/shaderfx.html). Their subsurface scattering shader is another variation of the nVidia shader setup, and has more control for the waxiness, although I must say your skin looks a lot better. Their alien creature demo has some exaggerated waxy skin.

Maybe their shader could give you some new ideas. But I understand if you leave it at this, in any case thanks for your work!

Charles

[Son Kim]

migusan76,

i just tried your shader out tonight, and it rocks!

[migusan76]

hey Son, That is really awesome!! Thanks for sharing, its nice to see some use out of it.