Reply To: Polybook Morten Fjellheim (Arev)

[John Sanderson]

What I am saying is that it appears you are trying to create two different materials (with different values each for color/roughness/metalness), but nothing is plugged in to the factor of your mix node.  So it renders a 50/50 mix of the properties for both principled shaders. I do not think this is what you want.  You want some areas that are 100% rust and some that are 100% metal.  You need to create some kind of mask to differentiate (plugging your image into a high contrast color ramp could give you this for free).  You could then plug that mask into a mix shader factor or just plug it into your various value slots on a single principled shader.

There are two images, one is plugged into a color ramp (such that the output is grayscale) and the other appears to be a height map (these are usually grayscale).  But you could use a mix RGB with your material mask to plug colors into the color slot on a single principled shader rather than have two.

For the splotches, yes I am referring to their size.  I cannot see the image texture, but because the splotch size varies substantially between different parts of the mesh, I believe there is some kind of scaling issue, either on the mesh itself or with the UVs.  Fixing that would distribute the rust a bit more evenly.

Finally, if you combined the material mask with a curvature or AO map, the rust sections could be mapped to specific places on your model where moisture would be likely to accrue, rather than be governed by an image that probably was not designed with your lamp in mind.