ContextCleaner: see every entry in the Windows 11 right-click menu, and which app added it — on the Microsoft Store.

Last updated:

Guided workflow variation

Repair a broken STL file,and see every change first.

MeshMedic opens the STL, counts its holes, non-manifold edges, and inverted triangles, fixes them in one step, and paints every changed triangle blue so you can check the repair before a new file is written.

Open the STL, choose Repair, check the blue patches and the Before and After counts, then export a new STL beside the original.

Pay once. Own it forever.

One-time purchase on the Microsoft Store · No subscription · Instant install

Get it from Microsoft

Buy through the Microsoft Store—instant install, automatic updates, and a Microsoft receipt for easy expensing. No account needed on our site, and no subscription on Store purchases.

Full MeshMedic overview
One-time purchase No telemetry Local-first

windows · originals never overwritten · 3mf colors kept · nothing uploads

If this sounds like your week

The slicer flags the model, and the part is due tonight.

An STL is nothing more than a long list of loose triangles. Exporters, downloads, and quick edits leave gaps where faces went missing, triangles wound the wrong way, and corners where too many faces meet. The slicer then warns about errors, drops a wall, or fills a cavity it should leave empty, and the toolpath preview stops matching the part you designed.

Where tooling usually breaks

Fixing it blind costs filament and an evening.

Rebuilding the model in CAD can take longer than the job itself, and often nobody has the source design anymore. A large modeling suite asks you to learn a whole toolbox for one chore. Web repair sites want the customer's file on their server. And an automatic fix that reports nothing leaves you guessing whether the shape you send to the machine is still the shape you were given.

Where MeshMedic lands

Count the defects, repair them, check the result, then export.

MeshMedic reads binary or ASCII STL and lists each defect with a Before count. Choose Repair and the After column fills in while the 3D view paints every flipped or added triangle blue. Toggle Show before to compare. When it looks right, Export writes a new STL in the same flavor, and a short note records what was flipped, added, removed, welded, and split.

Pay once. Own it forever.

One-time purchase on the Microsoft Store · No subscription · Instant install

Get it from Microsoft

Buy through the Microsoft Store—instant install, automatic updates, and a Microsoft receipt for easy expensing. No account needed on our site, and no subscription on Store purchases.

Learn more about MeshMedic

windows · originals never overwritten · 3mf colors kept · nothing uploads

What you get

Feature highlights

Every defect counted

non-manifold edges, inverted triangles, and holes for every part, in a table with Before, After, and Status columns, and No defects found for a clean file.

One repair pass

welds coincident vertices, removes degenerate and duplicate triangles, splits non-manifold edges and vertices, orients every shell outward, and caps holes.

Every change shown in 3D

triangles the repair flipped or added turn blue, and Show before switches back to the mesh as it was, with inverted triangles in red.

3MF projects kept intact

colors, materials, components, build items, metadata, and the thumbnail come through, and only the repaired mesh is rewritten.

A before and after note

the counts for every part and the triangles flipped, added, and removed, ready to copy or save as a .txt file for the job.

Originals never overwritten, nothing uploaded

every export is a new file in the same format, and the app makes no network connections and has no account.

Especially when

  • Repair holes, non-manifold edges, and inverted triangles in an STL, OBJ, or 3MF without rebuilding the model in CAD
  • See exactly what a repair changed, with counts before and after and every changed triangle shown in 3D
  • Repair a 3MF in place, keeping its colors, materials, components, and plate layout instead of converting it to STL
  • Keep customer and client models on the PC, with no upload, no account, and the original file never overwritten

Who benefits

Real-world scenarios

A downloaded model that will not slice cleanly

A maker downloads a bracket from a model-sharing site. The slicer warns about errors, and the layer preview shows a missing patch on the top face where two triangles were never exported.

MeshMedic lists Holes 2 and Inverted triangles 4 as Found. After Repair, both rows read 0 and Fixed, the new caps show in blue, and Export writes bracket-repaired.stl next to the untouched download.

A print shop checking a customer file

A customer emails an STL exported from an older CAD package for a same-day job. The shop wants to know what is wrong with it before anyone touches the slicer settings or quotes the time.

The operator opens the file, reads the Before counts, repairs it, and saves the note as a .txt file with the job. If the customer asks what changed, the note lists the counts before and after and every flipped and added triangle.

An ASCII STL written by a script

An engineer generates parts as ASCII STL from a script. One generated part has its faces wound the wrong way, so the slicer treats the part as inside out.

MeshMedic reads the ASCII file, flips the inverted triangles so every shell faces outward, and writes the export as ASCII STL again, so the rest of the pipeline reads it the same way it read the original.

Deep dive

What an STL repair changes, step by step

Reading the file. MeshMedic opens binary and ASCII STL. Because STL stores every triangle with its own three corners, it first welds corners that sit at the same position, so the counts describe the real surface rather than a pile of separate triangles. The file label shows the name, the format, the number of parts, and the triangle count.

Counting the defects. The table has four columns: Defect, Before, After, and Status. Non-manifold edges are edges shared by three or more triangles. Inverted triangles face the wrong way compared with the rest of their shell. Holes are closed loops of open edges. Degenerate and duplicate triangles get a row of their own when the file has any. A clean file shows "No defects found".

The repair. Choose Repair and MeshMedic runs one pipeline: it welds coincident vertices, removes zero-area and duplicate triangles, splits non-manifold edges and vertices, clears away stray fragments too small to enclose a volume, turns every shell so it faces outward, and caps holes with new triangles that face the same way as their neighbors. The mesh as it was stays in memory, so Show before can still draw it.

Checking it in 3D. The preview draws triangles the repair flipped or added in blue, labeled Changed by repair. Drag or use the arrow keys to orbit, scroll or press plus and minus to zoom, and press Home to reset the view. Show before switches between the mesh as it was, with its inverted triangles in red, and the repaired mesh.

Writing the export. Export opens the Windows save dialog with a suggested name, such as bracket-repaired.stl. A binary STL is written as binary and an ASCII STL as ASCII. Each kept triangle carries its attribute bytes across, which some programs use for color, and normals are recomputed from the corrected winding.

Keeping a record. After the export, the note shows the source and export names, the counts before and after for every part, and the changes: triangles flipped, added, and removed, and vertices welded and split. Copy puts it on the clipboard, and Save note writes it as a .txt file.

Trying it on your own files. The Microsoft Store runs a 15-day free trial with every feature, so you can repair the STL that gave you trouble last week and compare the result in your slicer.

How it is built

Built to change the mesh and nothing else.

Originals never overwritten

Every export is a new file you name. Saving over the original is refused, even through a junction, a hard link, a network path, or after the original was renamed or moved.

The rest of the 3MF untouched

Other entries in a 3MF package are copied byte for byte, and inside the model only the repaired vertices and triangles are replaced, so colors, materials, components, and build items come through.

Nothing uploads

MeshMedic runs in the Windows app sandbox with no declared capabilities, makes no network connections, and has no account and no telemetry. One-time purchase in the Microsoft Store.

FAQ

Straight answers—no glossary dump

How do I repair an STL file with MeshMedic?

Choose Open file and pick the STL. MeshMedic counts its non-manifold edges, inverted triangles, and holes in the table. Choose Repair, check the After column and the blue triangles in the 3D preview, and use Show before to compare. Then choose Export and save a new file; MeshMedic suggests the original name with -repaired added. The before and after note appears as soon as the export is written.

Which STL defects does MeshMedic repair?

It repairs non-manifold edges, where three or more triangles share one edge; inverted triangles, which face the wrong way; and holes, which are loops of open edges. Along the way it welds duplicate vertices, removes zero-area and duplicate triangles, and clears stray fragments too small to enclose a volume. The table shows each defect before and after, with a status such as Fixed.

Can it open ASCII STL as well as binary?

Yes. MeshMedic reads binary and ASCII STL, including ASCII files with Windows, Unix, or classic Mac line endings and facets written on a single line. The export keeps the same flavor: a binary file is written as binary STL and an ASCII file as ASCII STL, so the other tools in your workflow read it the same way they read the original.

What happens to my original STL, OBJ, or 3MF file?

It stays exactly as it was. MeshMedic reads the whole file into memory when you open it and writes every repair to a new file you name in the Windows save dialog, with the original name plus -repaired suggested. Saving over the original is refused, even when you reach it through a shortcut folder (junction), a hard link, a network path, or after it was renamed or moved. You can repair the same original as often as you like.

Where do my files go, and how do I get MeshMedic?

They stay on your PC. MeshMedic runs in the Windows app sandbox with no declared capabilities, makes no network connections, has no account, and collects no telemetry. It opens only the files you pick and writes only the files you save. MeshMedic is a one-time purchase in the Microsoft Store, and the Store runs a 15-day free trial with every feature, so you can repair your own files before you buy.

Related pages

Non-manifold edges, split apart and counted to zero. Fix the mesh errors before the slicer has to guess. STL repair for Windows 11, with nothing uploaded.

A broken STL or 3MF in.
A repaired file out, with every change shown.

MeshMedic counts holes, non-manifold edges, and inverted triangles, repairs them in one step, shows every changed triangle in 3D, and writes a new file in the same format, with a 3MF’s colors and components kept. Originals are never overwritten, nothing uploads, and the Microsoft Store runs a 15-day free trial.

Pay once. Own it forever.

One-time purchase on the Microsoft Store · No subscription · Instant install

Get it from Microsoft

Buy through the Microsoft Store—instant install, automatic updates, and a Microsoft receipt for easy expensing. No account needed on our site, and no subscription on Store purchases.

Open full product page

Technical specifications

Technical specifications for procurement

Spec Implementation
Data Sovereignty Reads only the STL, OBJ, or 3MF files you pick in the Windows open dialog; writes only the repaired file and the optional .txt note you name in the save dialog, refusing to save over the original by any path; the Recent list stays in the app’s own storage on this PC
Telemetry Status None; no account, no telemetry, and no network client in the app
Core Runtime .NET 10 and WinUI 3 (Windows App SDK 2.5), packaged as MSIX and run in an AppContainer with no declared capabilities; repair engine and STL, OBJ, and 3MF readers and writers in managed C#; 3D preview drawn with Direct3D 11
Network Requirements Fully functional offline; the package declares no capabilities, including no internet access, and the app makes no network connections
Deployment Compatibility Windows 10 version 2004 or later and Windows 11, x64; one-time purchase on the Microsoft Store with a 15-day free trial
Inputs STL (binary and ASCII), OBJ, and 3MF, picked in the Windows open dialog or reopened from the Recent list of the last 25 files
Checks Non-manifold edges, inverted triangles, and holes for every part, plus degenerate and duplicate triangles; Before, After, and Status columns; No defects found for a clean file
Repair Welds coincident vertices, removes degenerate and duplicate triangles, splits non-manifold edges and bow-tie vertices, clears stray fragments, orients every shell outward, and caps holes
Preview 3D view with repaired and added triangles in blue, inverted triangles in red, and a Show before toggle; orbit and zoom with the mouse or the keyboard
Outputs A new file in the same format: STL in its original binary or ASCII flavor; OBJ with objects, groups, materials, and smoothing groups; 3MF with colors, materials, components, build items, metadata, and thumbnail kept; plus a before and after note to copy or save as .txt
System Direct3D 11 graphics recommended, with software drawing as a fallback; about 1 GB of available memory per million triangles, and 8 GB of RAM covers meshes up to about 5 million triangles in binary STL, 3MF, or OBJ