What counts as a hole?

A simple closed chain of boundary edges. The tool fills each loop with a fan triangulation and reports how many loops were filled.

Will every hole be repaired?

No. Ambiguous boundary graphs and complex non-planar loops may be skipped. The result reports skipped loops and remaining boundary edges.

Does it fix non-manifold edges?

No. Non-manifold edge splitting and self-intersection repair are separate operations.

Can it fill large or curved holes?

It fills simple boundary loops with a triangle fan. Large, branched, or strongly curved loops may be skipped or produce a flat patch; check the reported holes filled and skipped.

Does filling a hole change the outer shape?

The outer surface stays unchanged; the fill closes the boundary, usually as a flat fan. Inspect the result before printing if the hole is on a visible or loaded surface.

Mesh repair/Topology

Fill mesh holes (local)

Close simple boundary loops and download a filled binary STL. The Worker parses STL, OBJ, PLY, 3MF, GLB, or a self-contained glTF, finds boundary edges, and adds a fan triangulation without uploading the model.

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

Filled mesh

No upload

Filled mesh

Only simple boundary loops are filled with a fan triangulation. Non-planar or ambiguous holes may need a different repair; verify the result before printing.

Drop a mesh to fill holes

STL, OBJ, PLY, 3MF, GLB, or a self-contained glTF. Simple boundary loops are closed and the result downloads as binary STL.

.stl · .obj · .ply · .3mf · .glb · .gltf → STL

Drop a mesh to fill holes

STL, OBJ, PLY, 3MF, GLB, or a self-contained glTF. Simple boundary loops are closed and the result downloads as binary STL.

Choose a file

Max file size: 500 MB · No upload

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

How it works

1
Drop a mesh file in any supported format.
2
The Worker parses the mesh, welds unindexed sources, and builds an edge-incidence map.
3
Simple boundary loops are closed with a fan triangulation; ambiguous loops are reported and skipped.
4
Download the filled binary STL. No upload is performed.

What the numbers mean

Hole filling

A hole is a closed chain of boundary edges. A fan triangulation can close simple, roughly planar loops; it may not produce the best surface for complex non-planar holes.

Limits

This operation does not detect self-intersections, separate overlapping shells, or repair non-manifold edges. Verify the result with the manifold check and a slicer.

Printing notes

Run manifold-check after filling to see whether boundary edges were removed.
A flat plane has an outer boundary loop; filling it creates a closing sheet rather than a solid, so use the result with care.
Check the filled surface for flipped or overlapping triangles before printing.

Questions

References

· ISO/ASTM 52900
· Mesh topology: boundary loops and hole filling