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STL to 3MF converter
Use the STL to 3MF converter online to keep supported triangle geometry in a model container with explicit units. Review the dimensions before saving; this is not a recovered slicer project.
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FROM FILE TO FINISHED MESH
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Rotate the preview, save the output and verify it in your next application.
Convert an STL file to 3MF: check units and the model container
For STL to .3MF output, choose the STL, review its size and keep 3MF as the output format. An STL does not record real-world units, so confirm how its numeric coordinates should be interpreted. The STL 3MF converter cannot recover original colors, materials, assemblies or print settings from triangles alone.
To learn how to convert STL to 3MF reliably, reopen the downloaded model in the target slicer and compare a known dimension. Save the original STL and a separate slicer project if you need to retain machine settings.
Understand core 3MF models and slicer projects · Use the reverse 3MF to STL conversion
Processing limits
STEP input: 20 MB. STL, OBJ and 3MF input: 50 MB. Output is limited to 1.2 million triangles. Complex models may need simplification in the source application.
One file at a time. Processing stops after 90 seconds. Files remain in browser memory, and no conversion upload is performed. Replacing a file clears the previous result. Closing the tab releases its working data.
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STL to ZIP converterCalibration examples: source files and measured results
Synthetic calibration inputs converted with the current geometry engine on 18 October 2026. These checks measure the digital mesh; no physical printing was performed. Download the sources and repeat the conversion with the listed settings. STL contains no unit metadata; coordinates in these examples are interpreted as millimetres.
Only the file formats shown below were tested in these examples. They do not validate external application steps, recover native CAD history or generate printer G-code.
STL → 3MF · 20 mm
| Triangles | Dimensions (mm) |
|---|---|
| 4 | 20 × 20 × 20 |
Settings and checksums · JSON · Source file + Converted file · ZIP