Convert 3MF to AMF
Free 3MF to AMF converter that runs in your browser. See real dimensions before you download.
How to convert 3MF to AMF
- Drop your 3MF file onto the converter — it opens in your browser, nothing is uploaded.
- Check the preview and the dimensions in mm; fix units or the up axis in “Units & orientation” if the size or orientation looks wrong.
- Choose AMF as the output and click Convert. Several files download as one ZIP.
What carries over from 3MF to AMF
| 3MF | AMF | Result | |
|---|---|---|---|
| Colour / materials | Yes | Yes | Kept |
| Textures | No | No | — |
| Units stored in file | Yes | Yes | Written as mm |
| Separate parts | Yes | Yes | Kept |
| Usual up axis | Z | Z | Unchanged |
About 3MF files
3MF was designed by the 3MF Consortium, whose members include Microsoft, Autodesk, HP, Stratasys and Prusa, as a modern replacement for STL in additive manufacturing. A .3mf file is a ZIP archive following the Open Packaging Conventions. Inside it, an XML model part holds the mesh, while other parts can hold thumbnails, textures and metadata. Unlike STL, the mesh shares vertices between triangles, which makes files smaller and keeps the surface connected. The core specification defines units, build items with placement transforms, and several objects in one file. Extensions cover materials, slices and beam lattices. Bambu Studio, OrcaSlicer and PrusaSlicer save their projects as 3MF with their own settings stored in extra files, so a project from one slicer may open in another with the geometry intact but the print profile ignored.
About AMF files
AMF was standardised as ASTM F2915 and later ISO/ASTM 52915, with the aim of fixing the shortcomings of STL for additive manufacturing. A file is XML, optionally compressed as a ZIP, and describes one or more objects made of a vertex list and volumes of triangles. Unlike STL, it declares units, such as millimetre, inch or micrometre, and can attach colours and materials to volumes or even to individual triangles, with gradients between them. The specification also allows curved triangles, constellations that arrange several objects, and custom metadata. In practice it was overtaken by 3MF, which came from industry backers and gained support in Windows and the main slicers. AMF files still appear from some multi-material printers and research tools, and from older exporters in Cura, Slic3r and Meshmixer.
3D printing notes
For multi-colour and multi-part prints, 3MF is the format to use. Bambu Studio and OrcaSlicer open each part as a separate object, which lets you assign a different filament or setting to each one, and Prusa-family slicers do the same. Because the unit is stored in the file, a model does not arrive at the wrong size. Be careful with project files: a 3MF saved by Bambu Studio carries printer, plate and process settings that PrusaSlicer will not apply, and some slicers pick a different default when a model has no declared plate. MeshShift writes 3MF with several parts and keeps colours as base materials, and it reads 3MF for viewing, measuring and print checks.
Frequently asked questions
Is this 3MF to AMF converter free and private?
Yes. The conversion runs in your browser with JavaScript and WebAssembly, so your 3MF file is never uploaded to a server. There is no sign-up, no watermark and no daily limit; very large files are limited only by your device's memory.
Is 3MF better than STL for 3D printing?
For most modern slicers, yes. 3MF records units, supports colours and several objects, and compresses well, while STL has none of those. STL remains the safer choice when a tool, a resin printer or a print service only advertises STL support.
Is AMF better than STL?
On paper, yes: it has units, colour, materials and several objects. In practice STL is accepted everywhere and AMF is not, and 3MF now fills the same role with much wider support. Use AMF only when a specific tool or workflow requires it.