How to do procedural scuff generation in Blender3D?

Question

Blender

How to make scuffs on the model and on its corners?
About these places

Answer 1

Angle = the place where the normal changes abruptly.
It turns out that you can get world normal in the shader node and process it somehow. For example, you can apply the "edge detection" filter (not sure what it's called in blender) and take the RMS value over 3 channels. So we get the value of angularity. Next, apply perlin noise, mix colors, etc. to it.