Fix3DFileFile. Fix. Print.
Tool guides Processed on this device

Your STL stays here. It is processed in this browser—not uploaded, stored, tracked, or sent to an AI service.

Private STL repair

Fix broken STL files.
See exactly what changed.

Diagnose print-breaking geometry, repair STL files, and download a freshly checked copy — all without your model leaving the browser.

Original stays untouchedNo account or analyticsHonest before / after checks

Drop your STL here

or choose it from your computer

ASCII or binary STL · up to 100 MB and 2,000,000 triangles

Required before processingI agree to the Terms of Use and acknowledge the Privacy Policy. I understand automated repair can remove or alter geometry and does not verify printability or safety.

Browser-based STL repair

Understand the damage before you change the model.

Fix3DFile combines local mesh diagnostics, conservative repair, and optional solid reconstruction in one private workspace.

Open edges and holes

Finds boundary edges that prevent an STL surface from forming a closed solid.

Non-manifold geometry

Flags edges and vertices shared in ways that can confuse slicers and repair tools.

Duplicate and broken faces

Detects repeated triangles, zero-area faces, and inconsistent surface winding.

Disconnected shells

Counts separate mesh regions so unexpected fragments are easier to spot.

Before-and-after changes

Shows the original and repaired geometry together and records each repair step.

Solid rebuild deviation

Measures how far a reconstructed surface moved from the source model.

How it works

Repair an STL in three steps.

  1. 1
    Choose an STL

    Load an ASCII or binary STL. Processing begins locally in a dedicated browser worker.

  2. 2
    Diagnose and repair

    Review open edges, non-manifold geometry, shells, and other defects before choosing a repair method.

  3. 3
    Inspect and download

    Compare the result with the original, review the change record, and save a separate repaired copy.

STL repair FAQ

Questions before you repair.

Is my STL uploaded to a server?

No. Fix3DFile reads, analyzes, repairs, and exports the STL in your browser. The repair workspace does not intentionally upload or retain your model.

What STL problems can Fix3DFile repair?

Safe repair handles unambiguous defects such as duplicate faces, degenerate triangles, inconsistent winding, and simple planar holes. Solid rebuild can create a new closed surface when conservative repair is not enough.

Does a successful repair guarantee a safe print?

No. Geometry checks do not validate slicer settings, G-code, printer condition, material strength, dimensions, or suitability for structural or safety-critical use. Always inspect and test the result.

Which 3D file formats are supported?

Fix3DFile currently supports ASCII and binary STL files up to 100 MB and 2,000,000 triangles. Other 3D formats are not supported yet.

What is the difference between Safe repair and Solid rebuild?

Safe repair preserves the original surface and avoids guessing. Solid rebuild voxelizes the shape and reconstructs a new closed surface, which can seal severe damage but may alter small details or intentional openings.