Title^
Simply layers of different materials.
For instance painted metal; when the paint starts to come off at spots, you can see the metal and maybe some rust underneath the paint. Actually everything that is painted is a layered material. Or if you spill some oil on the floor or so.
Does that help?
Yeah as Martin says, it is no more and no less like in real life. When you have a cement wall and you paint it over with white paint, then two years later you paint it blue even though your wife wanted pink, that's a layered material that you try to emulate in Blender with the shaders. When Tony Stark has his Iron Man suit all in metal and he paints is with hot rod red, he is layering a paint coat on top of the metal. So yeah, same as in real life, no tricks or math.
Follow up question - It's mentioned multiple times that something "looks like a layered material" in the lesson - how can you identify that it does? Just practice? Since we can't exactly cut into the material and see multiple layers, that is.
Hi Chris uunbo ,
You are probably over-thinking this and without a timestamp, I don't know what is meant exactly, but for instance a car has paint (color) and on top of that a clear coat for protection and maybe also to make it look nice and shiny (or not) and possibly some wax or other finish on top of that. I don't know much about cars, but you get the idea.
Or think of make-up on a face. It will look different on different skin, or on wood....
Or just skin itself (with its underlying fat, muscles, veins...).