I have an existing 3D model in STL format and need the middle, circular section enlarged by roughly 6-10 cm while keeping the rest of the geometry untouched. Please: • Isolate the middle section, scale it uniformly so the diameter grows within the 6-10 cm range I’ll confirm once you inspect the file, and blend the transition smoothly with adjoining parts. • Preserve overall watertight integrity—no non-manifold edges or flipped normals. • Return the updated file in STL The task is straightforward for anyone comfortable with STL editing. Let me know what software you’ll use and how soon you can deliver the revised model.