col_steel

Painted structural steel for the collapse part — one shader covering the crane lattice (safety yellow), I-beam columns and window frames (graphite), the cable/chain rig and the forged wrecking ball (pit > 0 adds hammered normal pitting). Pattern space is object-local position via vertex color. Paint chips to bare metal at box-UV plate edges, rust blooms and streaks run down local height (rust scales coverage), and specular is a Blinn-Phong sun highlight plus a fresnel reflection of the shared dusk environment — the col_env copy must stay identical to col_sky.