What are free tools for fix STL 3D models?

Free tools for fixing STL 3D models include MeshLab, Netfabb Basic (via Autodesk Viewer), and Blender—all resolving common issues like non-manifold edges, holes, or duplicate faces. - **MeshLab**: Handles batch repairs and basic editing, great for bulk STL fixes. - **Netfabb Basic**: Automates repairs through Autodesk Viewer, ideal for 3D printing prep. - **Blender**: Provides manual control for detailed adjustments, plus full modeling capabilities. These tools help hobbyists or 3D printing users prep STL files (e.g., from Thingiverse) for error-free use. For beginners, start with Netfabb’s automated features for quick fixes, then try MeshLab for more control as you learn.