Fix any STL. In one click.
Diagnoses non-manifold edges, holes, degenerate faces, and duplicate vertices - then auto-repairs them. Hand the clean file straight back to the Meshcast mold generator without re-uploading.
Results
Adjust optimization
FAQ
What's a "non-manifold edge"?
An edge that three or more triangles share, or a triangle whose normal points the wrong way. Slicers can't tell inside from outside on a non-manifold mesh and either refuse to slice it or produce a mess. The auto-fix re-stitches the geometry so every edge is shared by exactly two triangles.
Will the auto-fix damage my model?
For sculpted / scanned models, no - VCGlib's repair preserves the visible surface. For models with very narrow or hair-thin features (under 0.2 mm), some detail may smooth out. Compare Original vs Fixed in the viewer before you download.
What if the auto-fix can't repair the file?
Some failure modes are too severe (e.g. dozens of overlapping shells from a CAD export). Open the file in Bambu Studio ("Auto Repair") or Blender (3D-Print toolbox) and re-export, then drop the result here.
Does the file leave my computer?
No. Repair runs inside your browser via WebAssembly. The file is loaded into memory, fixed, and the download is generated on your device. We never see your model.
Why is the file size smaller even with no simplification?
Most STL exporters write every triangle as an independent unit with three full vertex copies. Welding duplicates alone typically cuts file size by ~50 %.