Attached Link: My gallery posting of Jessi with makeup algorithm

Mariner is spot on.

If you want bruises everywhere, I think it would be pretty easy to do - very similar to the freckles algorithm. But this is usually not what you want, right?

Most people don't don't think in terms of 150 shader nodes, so it's easy to conclude you can't make precisely positioned shapes with shader nodes. But you can, and that is why I wrote Matmatic. 50 nodes, 100 nodes, no big deal, it's still two or three lines of code.

If you want precisely positioned bruises (or makeup, or scars) these can be done using a mathematically defined region, bounded by two interpolations. This is what I did to put Jessi's eye makeup exactly where I want it.

Here's the technique I used. I put Jessi's texture on the one-sided square. That's right, the OSS. Why? Because the geometry has nothing to do with the algorithm. It only cares about UV coordinates. The OSS let's me clearly see where on the texture map I'm making an effect. Also, the OSS renders really fast.

So develop the coordinates for your region of interest on the OSS, iteratively changing the values and rendering to see where the region ends up.

When you're done, apply the material to your figure instead.

Do you guys think this is long enough for Beta on Matmatic? Most people seem to think its working right, but I haven't seen anybody else post an original Matmatic material. So as far as I know, everybody is just using my demos. Which concerns me because I tend not to use certain nodes, and they could be buggy. Opinions?

 

---

Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)