STL Repair

Bambu Studio, Cura, PrusaSlicer and every print service run the same checks on an STL before they will slice it: is every edge shared by exactly two triangles, are there duplicate or zero-area triangles, is the surface closed. Scans, AI-generated models from Meshy or Tripo, Blender booleans and Dyntopo sculpts fail one or more of them, and the slicer either refuses the file or prints something with missing walls. This tool runs those checks and fixes what it can in one pass, then tells you exactly what it did.

What it repairs: triangles with NaN or infinite coordinates are dropped; collapsed (zero-area) and duplicate triangles are removed; edges shared by more than two faces and vertices shared by more than one fan are separated so the mesh becomes manifold; then every hole whose boundary is up to 500 edges long is closed with ear-cutting triangulation, the same method MeshLab uses. Nothing else is touched: no smoothing, no remeshing, no vertex is moved, so dimensions and details are exactly as modelled.

What it deliberately leaves alone: openings larger than 500 edges, such as a model whose whole bottom is missing or a scan cut in half. Closing those means inventing geometry you did not draw, and the honest fix is to cap it in your modeller or let the slicer's own repair decide. The report shows how many open edges remain so you know whether anything is left.

You get back a binary STL and a report: watertight before and after, holes found and closed, open edges before and after, triangles before and after, and each repair that was applied with its count. Files are processed on our server in isolated memory and deleted within 15 minutes of your download. Need the file smaller as well? The STL Compressor runs the same repair first and then reduces to the size you ask for.