- No real displacement
- Either noise stretched over the surface in one direction (U/V), darker in cracks (occlusion multiplied by noise), or multiple noises put together to create different colors (use layered noise to allow user one color and then HSV shift for another noise), but never all three of these.
- Affects specular, mostly cutting it off completely
- Mostly darkens the color of the object
The patina is currently only affecting the diffuse and specular maps because the patina really does not have a particular height or bumpiness, that is all coming from the roughness of the object.
Making the UI for this pattern was interesting, moreso trying to lay out the adjustable options in a logical manner. I do not promote all the parameters on a noise SOP so that the user is not bogged down by all the options. I also control the look of the shader to stay near the defaults this way.