Create a modular (almost) procedural female skin for cycles

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

Postby loki1950 » Sat Jun 17, 2017 1:53 am

Freckles are just pigment in the skin they do not have height at all so putting them on a displacement map is just wrong.

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

Postby blindsaypatten » Sat Jun 17, 2017 4:53 am

loki1950 wrote:Freckles are just pigment in the skin they do not have height at all so putting them on a displacement map is just wrong.


I had no intention of doing so. :shock:

I was trying to picture how the freckles were distributed and was thinking back to another thread where someone used a random texture to generate a sort of mountainous terrain, and then picturing that if you were to place a plane such that only the tallest peaks poked through it, and took areas on the plane intersected by the peaks you might get something like random freckles, depending on the properties of the random surface. It's just the thought that came to mind seeing the color ramps.

With these nodes
NoiseNodes.png

The scale in the noise node determines the size of the freckles
NoiseScale.png
Scale of 5 on the left, 50 on the right

As the upper stop is lowered only the darkest spots remain, the darkest spots being the peaks in my metaphor
NoiseThreshold1.png

The greater the reduction the fewer, farther apart, and smaller they will be
NoiseThreshold2.png

Raising the left stop will increase contrast and reduce variation in intensity. Scale and the two stops can be adjusted as necessary to get the desired size, spacing, and darkness
NoiseAdjusted.png


As in the other thread, I'm writing this all out like this to improve my own understanding.
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Re: Create a modular (almost) procedural female skin for cyc

Postby jujube » Wed Jun 21, 2017 11:08 pm

Renderman apparently also has something similar to what you're talking about in it's built in paint flakes procedural, with the ability to independently control flake size and density.

(I hope I don't sound like an advertisement, but i'm a little obssessed with it at the moment... so much cool stuff to geek out over)

https://rmanwiki.pixar.com/display/REN/PxrFlakes
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Re: Create a modular (almost) procedural female skin for cyc

Postby blindsaypatten » Thu Jun 22, 2017 12:21 am

Interesting. Because after working with the noise based freckles further, I became rather dissatisfied with them. The problem is that the number, size and shape are not independent, if you increase scale to get a larger number the size shrinks, and if you adjust to make them larger, the shape becomes increasingly irregular. It's the old three qualities, you can only pick two trade off.

I think I saw a method somewhere where you could use particles for this sort of thing, which would be great as you can specify the number of particles, have a random factor to the size, and even weight vertex groups to adjust density in different places. Unfortunately, I have no recollection of where I saw how to do it.

Did you overcome your issues with renderman hair?
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Re: Create a modular (almost) procedural female skin for cyc

Postby jujube » Fri Jun 23, 2017 11:56 pm

I think so... with one blend file, where I was testing hair, I got it working in a less intensive diffuse-only mode, showing that the geometry was there and I didn't have anything to worry about. Then I went and did some rendering with my other file, and it worked fine, but I was afraid to try turning off the hair particles, for fear that that would break it and it wouldn't turn back on?? I haven't worked on it much the past few days now, though. But I think I understand texturing in renderman now. That was one of the pieces of the puzzle I needed to figure out before I could post my tutorial.

(fun fact: there is a hair color function in renderman that useses melanin concentration. I struggled with figuring out how texture mapping works in renderman so that I could test the whole spectrum of hair color, on strands of hair growing out of the same cube. )
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Re: Create a modular (almost) procedural female skin for cyc

Postby RobBaer » Sat Jun 24, 2017 12:34 am

blindsaypatten wrote:..., the shape becomes increasingly irregular...

Irregularly shaped moles are one of the early signs of dysplastic nevi. Better get your model a melanoma screen. ;) ;)
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