3MF → STL · local conversion
Choose a 3MF model and download a binary STL without sending the design to a conversion server.
3MF → STL
3MF materials, colors and print metadata are not part of STL. Multiple 3MF bodies become one triangle mesh in the exported STL; verify scale and separate parts in your slicer if needed.
3MF can store multiple objects, units, colors, materials and print metadata inside one package. STL stores only a triangle surface. This converter keeps the printable geometry and writes it as a compact binary STL.
Drop a .3mf file into the converter, select Convert to STL and wait for the local download. Open the result in your slicer, confirm its dimensions and orientation, then apply print settings there.
Drag a .3mf file into the converter above, or click to browse. The file stays on your machine — the browser reads it directly and nothing is uploaded to a server. Files up to 50 MB are supported.
Conversion runs inside a Web Worker so the page stays responsive. The converter reads multiple named objects, each with its own transform, then flattens every visible mesh into STL output. Larger models take longer to parse; meshes with several hundred thousand triangles usually finish in a few seconds.
When conversion finishes, the download starts locally. The output keeps the original filename with a .stl extension. There is no account step, no queue and no watermark.
Open the result in PrusaSlicer, Cura, Bambu Studio, Chitubox and Simplify3D. Confirm dimensions and orientation before applying print or render settings. Because 3MF carries unit metadata and STL does not, the scale check matters here.
| 3MF | STL | |
|---|---|---|
| Full name | 3D Manufacturing Format | Standard Tessellation Language |
| File structure | ZIP archive holding XML part descriptions | flat binary file of triangle records |
| Geometry model | multiple named objects, each with its own transform | one unstructured triangle soup, no hierarchy |
| Stores color & materials | Yes | No |
| Carries unit metadata | Yes | No |
| Typically comes from | PrusaSlicer, Bambu Studio, Orca Slicer, Fusion 360 and Microsoft 3D Builder | the input every FDM and resin slicer accepts |
The usual situation: you have a .3mf file from a slicer project or CAD export, but the tool you need to use next only reads STL. PrusaSlicer, Bambu Studio, Orca Slicer, Fusion 360 and Microsoft 3D Builder all export 3MF, while PrusaSlicer, Cura, Bambu Studio, Chitubox and Simplify3D typically expect .stl. Practically every slicer treats STL as its baseline input, which makes converting to STL the last step before a print job.
3MF stores multiple named objects, each with its own transform; STL stores one unstructured triangle soup, no hierarchy. Color, materials and textures do not survive the conversion — that is a property of the STL format itself, not a limitation of this converter. 3MF records units explicitly and STL does not, so you confirm dimensions after import. The geometry itself — triangle faces and vertex positions — is preserved in full, and that is what printing and downstream modeling actually depend on.
The model is tens or hundreds of times too large or small. Units did not line up; rescale in millimeters inside your target application. The output is empty or partial. The source may keep geometry on hidden nodes — unhide them and re-export from the original tool. Surfaces render black or inside-out. The converter recomputes normals for meshes that lack them, but faces that were already inverted in the source need fixing in PrusaSlicer, Cura, Bambu Studio, Chitubox and Simplify3D. The file will not open. Check that the extension matches the real format; a fresh export from the source application usually resolves it.
Most online converters upload your file to a server, convert it there and send the result back. For unreleased product designs, client models or anything under NDA, that upload is the moment the file leaves your control. This converter runs three.js loaders and exporters locally in your browser, so the file never crosses the network — the page will even convert with your connection turned off.
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