Create a modular (almost) procedural female skin for cycles

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Create a modular (almost) procedural female skin for cycles

Postby wolgade » Fri Mar 31, 2017 10:46 pm

Part 1: Basic skin

This approach is based on http://www.blendswap.com/blends/view/67519 which is licensed CC-BY-SA. The original file uses vertex colors for things that can't be done procedurally. I replaced vertex colors with masks using the default UV-layout. This way the skin fits your exported character without additional work. I used a scale of 1m = 1BU. If you use a different scale you will have to change some settings, especially those which rely on generated texture coordinates.
img01.jpg

Let's have a look inside.
img02.jpg

Ok, it looks a bit complicated, but it isn't. Let's start with displace section. It's just a voronoi texture using generated coordinates. The color ramp maps the voronoi pattern to values between grey and black since we only want negative displacement. RGB Mix controls the amount of displacement.

The diffuse part is just multiplying colors generated by noise textures with different scalings.

1. mask spots

img03.jpg

This node uses UV coordinates and an image texture to control freckles. Here's what it does.
img06.jpg
img06.jpg (23.39 KiB) Viewed 6653 times

2. group_skin_noise

img04.jpg

Two noise textures and a voronoi texture provide the basic skin pattern. The result gets darkened depending on mask spots.

3. Skin_shader

img05.jpg

This could use a bit of improvement. I really still have a lot to learn about SSS.

This is our result so far.

img07.jpg
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Re: Create a modular (almost) procedural female skin for cyc

Postby wolgade » Fri Mar 31, 2017 10:51 pm

Part 2: Lips with lipstick

This part could also be done as a second material. I decided to go this way:
img08.jpg

img09.jpg


And here we see why I didn't use a second material. Skin displacement gets mixed with lips displacement. Lips displacement is done with a stretched voronoi texture. The lips mask is done the same way as "mask spots" in the skin node. You don't need this if you give your lips a separate material. The skin shader is the same as in the skin node. For lips with lipstick this could be probably replaced by a basic diffuse-glossy-fresnel setup.

This is what we get now:

img10.jpg
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Re: Create a modular (almost) procedural female skin for cyc

Postby wolgade » Fri Mar 31, 2017 11:04 pm

Part 3: Procedural areola

img11.jpg

This is more a proof of concept than useful. I'll discuss a simplified version. Otherwise it gets too confusing.

img12.jpg

Both areola node groups are identical. Note their different values for x- and y-position. These values define the center of the areola on the UV map.

img13.jpg

The areola node group looks like this:

img14.jpg

It simply creates a circular mask with x- and y-position as the center. Rect_to_polar is basic math, converting rectangular coordinates to polar coordinates.

img15.jpg

This is what it looks like:

img16.jpg


The more advanded areola node group isn't that much better.

img17.jpg


I guess this is where the procedural approach ends and texture painting starts.
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Re: Create a modular (almost) procedural female skin for cyc

Postby wolgade » Fri Mar 31, 2017 11:16 pm

Part 4:Make up

img18.png

Women already know: Yes, it makes the difference. The node itself is rather boring and in no way procedural.

img19.jpg

The shaders are simple diffuse-glossy-fresnel setups. Intensity is controlled by a value you can set multiplied with a mask. Using masks with the default UV layout is a bit of a waste of memory, but that's the price for portability. It might be a good idea to bake your textures once you're satisfied.

img20.jpg

Doesn't look too bad. You might get away with it quite often, but keep in mind:
The inside of the mouth is completely wrong.
The eyebags are wrong.
Nostrils are wrong.
Soles of feet and palms of hands are wrong.
Use real fingernails and toenails when visible!
You should deal with the ears. They're more redish and more translucent in real world.
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Re: Create a modular (almost) procedural female skin for cyc

Postby wolgade » Fri Mar 31, 2017 11:22 pm

Part 5?

No. I'll just attach the blend file here. All required textures are packed into this file. Blury masks were scaled down before. Masks that require sharp borders are 4096x4096 (lips e.g.).
Attachments
skin_4.blend
(5.4 MiB) Downloaded 393 times
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Re: Create a modular (almost) procedural female skin for cyc

Postby Mindfront » Sat Apr 01, 2017 10:29 pm

Thanks! I must definitely try this as I think it would be a great complement to a textured skin. Sometimes I prefer procedural textures as one have greater possibilities to make random patterns.

Skin SSS is in my opinion very difficult. I have seen alot of different solutions for skin SSS but never got them to work fully satisfying e.g. many do their great looking skin shaders with SSS on a giant head but the same shader does not work on a normal scale character.
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Re: Create a modular (almost) procedural female skin for cyc

Postby wolgade » Sun Apr 02, 2017 10:14 am

Mindfront wrote:Thanks! I must definitely try this as I think it would be a great complement to a textured skin. Sometimes I prefer procedural textures as one have greater possibilities to make random patterns.

I did the procedural texture for several reasons.

I wanted to see how far you can get with this approach. It works quite good for providing a general diffuse pattern. If you bake the diffuse you get a good starting point for texture painting. The default uv-layout uses different scales for the uv islands making it difficult to just use Gimp or Photoshop to generate a skin pattern. Procedural textures also work quite good when it comes to close-ups. Procedural textures don't get blury. They always provide the necessary level of detail. You'd need very big image textures to do close-ups with the default uv-layout. This is also true for skin bump / displace.

Another reason for using a procedural texture instead of an image texture based on photographs: Photographs of real human beings generate two legal issues. The copyright of the photographer and the human rights of the model. http://www.makehumancommunity.org/forum/viewtopic.php?f=15&t=12094&start=10
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Re: Create a modular (almost) procedural female skin for cyc

Postby Mindfront » Mon Apr 10, 2017 11:58 pm

wolgade wrote: Procedural textures also work quite good when it comes to close-ups. Procedural textures don't get blury. They always provide the necessary level of detail.

Yes, with procedural textures one can use lower resolution (free MakeHuman) skin textures and let the procedural textures spice the details.

wolgade wrote:You'd need very big image textures to do close-ups with the default uv-layout. This is also true for skin bump / displace.

I know :lol: I had very hard time to find good high resolution photo reference images and when I did they had a price both money and time spent on painting.
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Re: Create a modular (almost) procedural female skin for cyc

Postby wolgade » Tue Apr 25, 2017 11:54 am

I made some changes to my node setup for two reasons:

1. Redo the skin shader and use SSS the right way. I learned this from a link Joel provided a while back http://www.makehumancommunity.org/forum/viewtopic.php?f=7&t=14196.
2. Reorganize the node setup for better reusability of the node groups.

1. Skin shader

1.jpg
Yes, you plug a colour into a vector input. That's the whole secret. And now SSS actually does something.

<rant> I never would have tried. Years ago when I had to learn some programming I had to use Pascal, a language that doesn't allow to mix data types. C guys do this often to safe time. Time they need afterwards to hunt the bugs they created this way. Anyway, back to Blender: I connect sockets with matching colours or use a converter. If I'm supposed to plug a colour into a socket, why is this socket of type vector? </rant>


2. Reorganize node setup

2.jpg
We now have the two groups skin pattern and areola pattern. Both output a colour instead of a shader. Two advantages: You only have the slow skin shader once and you can easily reuse especially the skin pattern. This is how it looks:
3.jpg
4.jpg
In the second image I only used the rim light. You'll notice the translucency of the ears created by SSS.


Now let's reuse some node groups with an image texture!

5.jpg
I used young_lightskinned_female bundled with MH as diffuse texture. Here's a close-up:
6.jpg
Not that bad given the fact that the image texture has a resolution of 2048x2048. The attached blend file does not include any image textures as I already included them in my first upload.
Attachments
skins.blend
(5.5 MiB) Downloaded 396 times
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Re: Create a modular (almost) procedural female skin for cyc

Postby blindsaypatten » Thu Apr 27, 2017 2:13 am

Looking good wolgade. If it's easy to do it would be interesting to see the exact same view of the default rendering of that closeup under the same lighting etc.
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