You can do it yourself, no need to spend money you don’t need to spend, or use cookbook formulas. All it takes is a little knowledge and a little thought…and some clay. So go out and get a some clay. I’ll wait…
No, seriously, the best way to develop a shader for anything is to get it in your hands and look at it. Second best is get a photo.
So get some clay and hold it up to the light. What do you see?
It has color. That’s obvious. If you hold it up to a bright light, does light pass thru it, or is it totally opaque? Well, you can see that no light passes thru. It’s not transparent like a window, and light doesn’t pass thru. Can you see stuff on the other side? No.
Okay, so now you know it has color, and has no “translucency”, because light doesn’t pass thru it (trans - thru, and lucent - light). And it’s not “transparent” like a window. But one more thing you’ll probably notice is that it kind of glows around the edges. It’s very subtle, but it’s there. That’s because light enters the clay, bounces around inside, then comes back out and into your eyes. But it only does that around the surface, forming a kind of glow around the edges. That’s called “subsurface scattering”, because it’s light scattering under the surface then coming back out.
We also know that clay has a highlight that is spread around the surface broadly. And it also has a slightly bumpy surface, though it’s very slight.
Now, keep in mind that shaders are only a part of what convinces viewers about a material. If you want people to believe it’s clay, it generally has to be shaped like clay. Which means a big blob with a flat bottom and a lot of indentations where fingers have been poking at it. And of course the lighting has to be right.
Anyway, here’s a quick shot at some clay. Took a sphere, ran it thru bullet to get the blobby effect, did some quick modelling to get the pokey fingers effect, and added some bump. The rest of the shader was pretty much as I described, though the subsurface scattering was very subtle.
The result is kinda sucky, looks a little too plasticy…but then again I broke my own rule and didn’t use a reference.
Click thumbnail to see full-size image