# Mesh Fixer

> Loft Mesh Fixer is a free in-browser mesh repair tool that turns a broken, open, or non-manifold STL / OBJ / PLY mesh into a watertight, manifold solid using signed-distance-field remeshing. It also boolean-combines two meshes (union, subtract, intersect) through a real CSG kernel with an honest result report, and reconstructs a watertight surface from a PLY point cloud via winding-number reconstruction. Everything runs locally in WebAssembly — no upload, install, or signup — so confidential CAD never leaves your device.


Live tool: https://lofttools.com/tools/open-tools/mesh-fixer

Category: Open Anything


## What it does

- One-click Heal — remeshes an open / cracked / non-manifold mesh into a watertight, manifold solid (SDF repair)
- Boolean combine — union, subtract, or intersect two meshes through a real CSG kernel
- Honest result report — volume, area, triangle count, component count, genus, and a watertight verdict
- Point cloud reconstruction — rebuild a watertight surface from a PLY point cloud (normals estimated if absent)
- Refusal is explicit — a boolean on a non-watertight operand tells you the open-edge count and to Heal first
- Chainable — heal a mesh, then boolean it, then export, without re-importing
- STL (binary + ASCII), OBJ, and PLY input; STL and OBJ export
- Shaded, shaded-with-edges, and wireframe display modes
- Runs entirely in WebAssembly — files never leave your device
- Works offline after the first visit (PWA cache)

## How it works

1. **Open a mesh** — Drag an STL, OBJ, or PLY file into the browser, or click Open mesh and pick one. It loads instantly — nothing leaves your device.
2. **Heal to watertight** — Click Heal to remesh an open, cracked, or non-manifold model into a watertight, manifold solid. The result report shows the new triangle and vertex counts.
3. **Boolean-combine (optional)** — Open a second mesh as Mesh B, pick Union, Subtract, or Intersect, then click Combine. The report shows volume, genus, and whether the result is watertight.
4. **Export** — Click STL or OBJ to download the repaired or combined mesh.

## FAQ

### What does "watertight" mean?

A watertight mesh is a closed, manifold surface with no holes, no boundary edges, and no non-manifold edges — every edge is shared by exactly two triangles. Heal rebuilds your mesh to that standard so it is valid for 3D printing, boolean operations, and volume measurement.

### Why was my boolean refused?

Boolean operations require both operands to be watertight solids. If an operand has open or non-manifold edges, the tool refuses rather than return garbage, and reports the open-edge count. Run Heal on that mesh first, then retry the boolean.

### Will my file leave the browser?

No. Importing, repair, the boolean kernel, and reconstruction all run in your browser tab via WebAssembly. Nothing is uploaded to a server.

### What formats are supported?

Input: STL (binary and ASCII), OBJ, and PLY (meshes and point clouds). Export: STL and OBJ. Point cloud reconstruction reads PLY points.

### Can it rebuild a mesh from a scan or point cloud?

Yes. Load a PLY point cloud via Points → mesh and it reconstructs a watertight surface using winding-number reconstruction. If the PLY carries per-point normals they are used directly; otherwise normals are estimated.

## Tips

- **Heal before you boolean** — Union, subtract, and intersect need watertight operands. If a combine is refused, run Heal on the offending mesh first, then retry.
- **Chain operations** — Each result replaces the on-screen mesh, so you can heal, then boolean, then export — no need to re-import between steps.
- **Confidential CAD stays local** — Mesh bytes load straight into WebAssembly — nothing reaches a server. Open client files on shared or hotel computers safely.

## Privacy — what we do not do

This tool runs entirely in the browser via WebAssembly. Your file never reaches a Loft Tools server. Specifically:

- **No upload.** The file bytes load into the browser tab's memory and process on your own CPU. Open DevTools → Network and observe zero outbound requests carrying file data while Mesh Fixer runs.
- **No AI training on your file.** Loft does not train models. We could not train on a file we cannot see.
- **No content scanning.** No virus, copyright, or content-moderation pass against your file. The bytes are not accessible to us.
- **No server-side log of file contents, filenames, or EXIF metadata.** Cloudflare edge captures URL and truncated IP for abuse defense (standard CDN behaviour). Cloudflare Web Analytics records anonymous page hits, no cookies, no PII. Nothing about your file content reaches any log.
- **No retention.** Close the tab and the file leaves browser memory. No backups exist on our side because no copy ever existed on our side.
- **No account.** No email, no signup, no auth, no telemetry tied to you.
- **Offline-capable after first visit** (PWA). Once you've loaded a tool, it caches; later sessions work without internet. For high-sensitivity files, run the tool once online to warm the cache, then disconnect before processing.

Compare with upload-based services: each transmits your file to a processing server. Even over HTTPS, each has logs, retention windows, and subpoena exposure. Loft has none of these because the server architecture does not include your file.

## More

- All tools: https://lofttools.com/tools
- Category: https://lofttools.com/tools/open-tools
- LLM index: https://lofttools.com/llms.txt