wet_iron

The surface of the dead colossus. A metallic-roughness shader that computes its weathering from world position rather than sampling it, so one material covers a 190 m silhouette seen from the sea and the pitted plate a climber has a hand on.

Four layers ride on the base metal: rust (low-frequency blotches biased toward upward faces and toward the geometry's vertex-colour alpha, which is the author's wear mask), salt bloom (on the faces the storm drives against, strongest below salt_height), grime (vertical runs stretched along Y), and a wet film that narrows the specular lobe and thins out above wet_height, so the base of the tower shines and the crown is dry and cold.

Vertex-colour RGB tints the base metal, so brass hardware, verdigris seams and black iron all come off the same material — the geometry carries the difference. A fine noise gradient tilts the shading normal for pitting at close range.

Materials made from it: spine_iron, spine_plate, spine_brass, spine_verdigris, spine_rust, spine_lamp, spine_beacon.