abstract 3d model

Adult thyroid gland, exact same bilobed butterfly geometry and 55 × 20 × 15 mm outer dimensions as the previously generated cancer model, BUT with the 12 mm tumor nodule completely removed: surface smooth, no irregularities, uniform dark-pink hue, isthmus thickness identical to the cancer version. Output a single watertight STL file, 40–60 k triangles, Z-up, no cartilage, no trachea, no base stand.