Fix problem STL meshes: weld duplicate vertices, remove degenerate faces, and detect non-manifold boundaries. Browser-based, zero upload.
Upload your problematic STL file
We weld near-duplicate vertices (0.001 mm tolerance), drop degenerate triangles, and scan boundary edges
Download a cleaner STL plus a manifold report with the boundary-edge count
0 bytes uploaded. STL Hole Repair runs entirely in your browser using three.js and WebGL. Your meshes never leave your device.
Three things: degenerate triangles (zero-area faces) are dropped, near-duplicate vertices are welded to a 0.001 mm grid, and boundary edges (the symptom of holes) are counted so you can decide whether the mesh is print-ready.
Not yet — the metrics tell you how many boundary edges remain after welding. For complex holes, run the result through Meshmixer or Microsoft 3D Builder to fan-fill the boundary loops. Auto fan-fill is on the roadmap.
Beyond welding vertex duplicates within 0.001 mm and removing zero-area faces, the original geometry is preserved bit-for-bit.
If the post-repair Boundary edges metric is 0 the mesh is manifold and ready to slice. Anything > 0 means open holes remain — fix them in a desktop tool before printing.
Strip duplicate triangles and zero-area faces from STL/OBJ meshes. Smaller files, faster slicing, fewer printer errors.
Open toolRecompute consistent face and vertex normals on any STL/OBJ/GLB. Fixes inverted shading, missing normals, and flipped triangles.
Open toolFind walls thinner than your minimum print threshold. Ray-cast across the mesh to detect thin sections that may fail to print or break. Browser-based.
Open tool