Your topology 3D model overlaps in paid software typically due to mesh issues: non-manifold geometry, unintended extrusion, or flawed boolean operations that create intersecting faces.
Non-manifold geometry (edges shared by more than two faces) confuses the software’s volume calculation, while accidental extrusion or messy boolean cuts often leave overlapping parts that break the model’s structure.
To fix this, use the software’s mesh cleanup tools (e.g., "Make Manifold" or "Check Geometry") to identify and resolve overlapping areas step by step.