So I found this addon/project called Mech/fy.
It is fun messing with it though I dont understand how materials work. There are 3 material slots and materials asigned to those slots are mixed on the model in certain proportions and patterns. I dont understand how do I adjust the way materials are being mixed. None of the materials doesnt seem to have any nodes controlling how are they being mixed with each other.

If you want to check it out you need custom sculpting branch of blender, although this file kinda works in regular 2.8 , at least if you want to see how materials work.