Vertex paint/weight and material effect.

I’ve been playing about with node only effects for rust recently. While I can get a really nice rusty effect I have no real control over where the patches are applied, I’m bound by the underlying texture, musgrave or noise.

Is there a way for verts to attract a material effect with paint or weight? To mimic the way rust tends to grow from edges and corners. I’ve only tried a little painting when messing around with sculpting, and I know nothing about weights yet.

If this is possible could someone please nudge me in the right direction, or is there another way to achieve this?


Try searching for “dirty vertex colors” or “geometry node pointiness” and use those e. g. as inputs for the Fac value of a Mix shader.

This is an example from the time before the pointiness value was introduced into Blender with links to tutorials for baking ambient occlusion and cavity maps. Just replace the black patina in that silver with rust in your imagination and you’ll get the gist.