3MF to STL Converter
Convert 3MF files to STL directly in your browser. Your model is processed locally and never uploaded.
Your 3MF stays on this device. MeshWrench converts it to STL locally in your browser.
Up to 150 MB. STL cannot store color, materials or textures — surface geometry only.
Processed locally — nothing was uploaded.
- File name
- File size
- Source unit
- Output scale
- Millimeters
- Triangles
- Mesh objects
- Build items
- Component instances
- Width
- Height
- Depth
Batch processing is a Pro capability.
Pro batch tools are being prepared. Purchasing is not available yet.
Drag files here, or click to browse
3MF files only, same limits as single-file conversion.
How to convert 3MF to STL
- Select a 3MF file using the picker above.
- MeshWrench unzips and parses the package locally, in a background worker — nothing leaves your device.
- Review the preview, dimensions and any warnings, then download the converted STL file.
What is preserved
The converter resolves your 3MF package's full build scene: mesh objects, component objects (including nested components), and every build item's placement transform, including mirrored/reflected instances. The output is one flattened triangle mesh with correct geometry and consistent, outward-facing normals.
What is not preserved
STL stores surface geometry only. Colors, base materials, textures, UV coordinates and 3MF metadata are not included in the download — this is a limitation of the STL format itself, not something MeshWrench chooses to drop. If your file includes any of these, a warning appears before you download.
How units are handled
3MF stores measurement units explicitly. STL does not, so MeshWrench converts the geometry to millimeter-scaled coordinates for broad slicer compatibility. Micron, millimeter, centimeter, inch, foot and meter are all supported source units — the detected unit is shown after conversion.
3MF versus STL
3MF is a modern, XML-based package format that can store color, materials, units and metadata alongside the mesh. STL stores only raw triangle geometry, with no units and no metadata, but remains the most widely supported format across slicers and CAD tools — which is why converting to it is useful even though it's the simpler format.
Why colors and textures are lost
This isn't a bug or a missing feature to fix later — the STL format has no field for color, material or texture data at all. Any 3MF-to-STL conversion, from any tool, loses this information by definition.
Is the file uploaded?
No. There is no server-side conversion route in MeshWrench. Your browser reads the 3MF package, unzips and parses it, and builds the STL file, all on your device. You can verify this yourself: open your browser's developer tools, watch the network tab, and convert a file. No request containing your file will appear.
Common conversion errors
- The file isn't a valid ZIP/3MF package, or its package data is corrupted.
- The package is password-protected (encrypted), which can't be read locally.
- MeshWrench can't find a 3D model part inside the package.
- The model XML is malformed, or declares a measurement unit MeshWrench doesn't recognize.
- The model has no build items, so there's nothing to export.
- The model is more complex (triangles, nested components) than this tool's safety limits currently allow.
Frequently asked questions
Is my 3MF file uploaded?
No. The package is unzipped, parsed and converted entirely in your browser, inside a background Web Worker. It's never sent to a server — check your browser's network tab while a file converts to confirm this yourself.
Are colors, materials and textures preserved?
No. STL stores surface geometry only — no color, material or texture information exists in the format. If your 3MF file includes any of these, MeshWrench shows a warning before you download, but the STL itself never contains them.
What units does the downloaded STL use?
3MF stores measurement units explicitly (millimeters, inches, and so on) — STL does not. MeshWrench reads your file's declared unit and converts the geometry to millimeter-scaled coordinates, since that's the broadly compatible convention most slicers expect.
Does this converter repair or validate the geometry?
No. This tool only converts format — it doesn't check for or fix holes, non-manifold edges or flipped normals. STL Checker and STL Repair are planned as separate tools.
Why did my conversion fail?
Usually because the package is corrupted, encrypted, or doesn't contain a recognizable 3D model — see "Common conversion errors" below for the full list MeshWrench checks for.