External spiral stair

External spiral staircase, a 3m tall single-floor section climbing around a slim riveted iron column with pierced plate treads and a curling filigree handrail at 1.0m, flat top and bottom landings so sections stack to reach any floor line.

风格：low-poly, flat-shaded vertex colors, no textures, single shared material, so any set of these merges to one draw call; shares palette and scale with its kit