Greenhouse Module

Greenhouse tunnel module, footprint exactly 8x4m, 3m tall, cyan translucent panel vault over a gunmetal frame, a standard airlock collar (3m wide, 3m tall, orange ring) centered on one 4m end face flush at the footprint edge; other walls clean and flat.

风格：low-poly, flat-shaded vertex colors, no textures, 2 materials: the shared opaque one plus a distinct surface (glass, water or chrome), which stays its own mesh through mergeAssets rather than merging into the rest; shares palette and scale with its kit