Finding 01 · Check before export
Normal direction mismatches
Facet normals can be recalculated from triangle winding.
Safe preview
Fast STL fixer
A quick STL fixer for common 3D print mesh problems.
Start with one upload, get a mesh health score, and run a conservative repair preview for supported issue families.
- One-step upload to report
- Safe repair action log
- Export gate stays explicit
Start STL fixerBrowser-local first pass
Diagnostic bench
Upload your STL to start the fixer
The fixer checks common mesh defects first, then lets you preview only the repair actions that are safe in V1.
Start STL fixer9
Finding 02 · Check before export
Duplicate faces
Repeated triangles are removed from the preview mesh.
Safe preview
Inspection focus
When to use the STL fixer page
Use this page when you want the shortest path from upload to safe repair preview.
- Run a quick mesh health score before a print deadline.
- Confirm whether issues are safe to preview or report-only.
- Create a private repair artifact only after reviewing the preview.
Repair boundary
Fast does not mean risky
The fixer keeps risky edits out of the automatic path so a fast workflow does not over-promise geometry repair.
Supported
- Common triangle cleanup
- Normal mismatch preview
- Before/after issue delta
Report only
- Self-intersections
- Complex non-manifold edges
- Manual sculpting or CAD edits
FAQ
Questions before the next print
Is this STL fixer automatic?
It can automatically preview safe repair candidates, but it still reports risky topology instead of silently editing it.
What makes a repair action safe?
Safe actions remove or recalculate mesh noise without trying to infer missing geometry or redesign the model.
Can I use it just as a checker?
Yes. You can stop at the issue report and use it as a diagnostic STL checker without creating an export artifact.
Related diagnostics
Continue the diagnostic path
01
Free STL Checker
Upload an STL file to check mesh health, open-boundary hole signals, non-manifold edges, triangle counts, dimensions, and repairability.
02
Fix STL File Issues
Find why an STL file fails in a slicer and preview safe fixes for duplicate faces, degenerate triangles, and normal mismatches.
03
STL File Repair Reports
Generate an STL file repair report with issue severity, safe repair actions, before/after deltas, and export boundaries.