aquarium rock cliff 3d model

Generate a watertight, manifold, FDM-printable 3D mesh (mm units): a slightly concave curved back panel insert for a cylindrical glass tube aquarium/terrarium. Front is a realistic stratified rock cliff with cracks (no fragile thin parts; min thickness 2–3 mm). Integrate: (1) bottom arched cave entrance with shallow interior, (2) 2–4 sturdy rock shelves/ledges, (3) small stone watchtower/ruin on a ledge, (4) an open water channel starting near the top and descending to a bottom outlet, forming 2–3 stepped waterfall cascades with small basins and side walls to prevent spillover. Back side mostly flat for mounting; avoid deep undercuts/self-intersections/inverted normals.