What does one-click repair actually fix?

Duplicate and degenerate faces, non-manifold edges, bow-tie vertices, inconsistent winding, simple holes, and optionally self-intersecting triangles. It does not reconstruct missing surfaces or guarantee printability.

Why did the triangle count drop?

The non-manifold stage removes excess faces on edges shared by three or more triangles, and the self-intersection stage removes every triangle involved in a crossing. Both operations can delete intended geometry, so compare the reported counts.

Can I keep the self-intersecting faces?

Yes. Disable the self-intersection stage before choosing the file. The repair still welds, fixes topology, closes holes and unifies normals, and the report will show the remaining crossings.

Does repair upload my model?

No. Parsing, all repair stages and STL writing happen in a Web Worker on your device. No file bytes are sent to a server.

What should I do if warnings remain?

Try the dedicated tool for the reported problem: repair-non-manifold, fill-holes, repair-self-intersections, or voxel-remesh. For complex models, separating the shells in CAD is usually more reliable.

Mesh repair/Topology

One-click mesh repair (local)

Repair a printable mesh in one local pass. The Worker welds duplicate vertices, removes degenerate and duplicate faces, deletes non-manifold junctions, splits bow-tie vertices, unifies winding, closes simple boundary loops, and optionally removes self-intersecting faces. STL, OBJ, PLY, 3MF, GLB and self-contained glTF input; binary STL output; no upload.

ReadyNo uploadWorkerSTL · OBJ · PLY · 3MF · GLB · glTF

Tool facts

Formats: STL · OBJ · PLY · 3MF · GLB · glTF
Output: Mesh file
Worker: Yes
Max file: 500 MB
Runs: in your browser

Why local

Repaired mesh

No upload

Repaired mesh

One-click repair chains local topology heuristics. Stages can be disabled below; the report lists removal counts and any remaining non-manifold, open-boundary, or self-intersection warnings. Inspect the result before printing.

Drop a mesh to repair

STL, OBJ, PLY, 3MF, GLB, or a self-contained glTF. One Worker pass welds vertices, removes non-manifold junctions, unifies normals, closes simple holes, and optionally removes self-intersecting faces; output is binary STL.

STL · OBJ · PLY · 3MF · GLB · glTF → STL

Drop a mesh to repair

Choose a file

Max file size: 500 MB · No upload

Repair stages

Remove non-manifold edges and bow-tie verticesClose simple boundary loopsRemove self-intersecting faces (may delete geometry)

No upload · File.slice() / ArrayBuffer → Worker → repaired STL.

How it works

1
Drop an STL, OBJ, PLY, 3MF, GLB, or self-contained glTF file.
2
Choose which stages to run: non-manifold repair, hole closing, and self-intersection removal are enabled by default.
3
The Worker parses and welds the mesh, runs the selected topology stages, and re-orients the winding.
4
Review the before/after triangle and vertex counts, removed-face counts, and any remaining warnings.
5
Download the repaired binary STL and confirm the result with manifold-check or your slicer.

What the numbers mean

Transform order

Welding and cleaning run first. Self-intersection removal is attempted next, then non-manifold repair and bow-tie splitting, then a final hole-fill pass and normal unification. The final step does not re-weld, so split bow-tie vertices stay separate.

counts

Removed degenerate and duplicate faces come from welding. Removed faces are excess triangles on non-manifold edges. Split vertices are bow-tie junctions duplicated into separate fans. Holes filled counts simple boundary loops closed after face removal.

warnings

A clean result means the final mesh is watertight, has no non-manifold edges, and the self-intersection pass found no remaining crossings. Warnings identify the checks that still fail; a stage may also be skipped when a mesh exceeds its limit.

Limits

Each stage uses local heuristics. Self-intersection removal deletes every triangle involved in a crossing and keeps a fill only when it stays clean. Complex damage, large self-intersecting regions, and geometry larger than the per-stage triangle caps need voxel remesh or manual CAD repair.

Printing notes

Run manifold-check on the downloaded STL and confirm non-manifold edges, boundary edges and intersecting pairs are zero.
Compare the before/after triangle counts; a large drop means the repair removed geometry you may still need.
If the result is not watertight, run voxel-remesh as a lossy fallback or repair the shell in CAD.
Always slice the repaired model before printing; a watertight mesh can still have thin walls or unsupported overhangs.

Questions

References

· ISO/ASTM 52900
· Mesh repair: welding, manifold topology and winding
· Manifold geometry and watertight surfaces