Convert AMF to 3MF Online
Upload an AMF file and get back a 3MF package that current slicers will open: one object, one triangle mesh, unit declared as millimeter. Color, material and curved-triangle data in the AMF are not transferred, and the coordinate numbers are passed through unchanged, so check the scale after you import.
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AMF files in Google Drive?
Drive cannot preview AMF files. Open one from Drive with MiConvert to turn the model in your browser, or convert it and save the result next to the original. MiConvert for Google Drive →
What AMF is, and what the 3MF you get contains
AMF (Additive Manufacturing File Format) is an XML description of a printable part, standardized around 2011 as a richer successor to STL, able to carry vertices and triangles, curved triangle edges, colors, materials and constellations of placed copies, sometimes shipped gzip-compressed. Adoption stalled, so the slicers people actually use today, like PrusaSlicer, Cura, Bambu Studio and Orca, expect STL, STEP or 3MF, and an AMF from an older tool chain usually has to be repacked before anyone can slice it.
On this page the work is done by a Python reader on our servers, not in your browser. It accepts plain AMF XML, gzip-compressed AMF, and AMF wrapped inside a ZIP. It walks every object in the document, collects its vertex list and triangle list, merges them into a single mesh, recomputes the facet winding so the normals point consistently outward, and then writes a 3MF package with one object, one mesh and the unit attribute set to millimeter.
Triangle geometry is what survives. Everything else the AMF format can carry is dropped: color and material entries, texture references, the curved-triangle edge data (curved triangles are written as the flat triangles their vertex indices describe), and constellations, so repeated placements are not expanded into copies. Multiple objects and volumes become one body, which matters if your AMF describes a two-material part: you get a single mesh and reassign materials in the slicer.
No step in the pipeline converts units. The AMF unit attribute is ignored and the raw coordinate numbers are copied into the 3MF, which then declares them as millimeters. An AMF authored in millimeters comes out the right size; one authored in centimeters, inches or meters comes out wrong by exactly that factor and needs a scale correction on import. The axes are written as they were read, so the part is not rotated on this route.
This conversion is for people holding legacy AMF exports who need a container a modern slicer accepts, and for anyone whose print farm or service bureau asks for 3MF specifically. If your slicer takes STL, that route carries the same numbers with one less layer of metadata.
How to convert an AMF file to 3MF
- Open the AMF in a text editor (or check the exporter settings) and note the unit attribute near the top. That tells you in advance whether you will need to rescale after import.
- Upload the file here. Plain .amf, gzip-compressed .amf and an .amf inside a ZIP are all read; the file is uploaded to our servers and converted there.
- Wait for the job to finish. Files of a few megabytes complete in seconds; very large multi-object documents are bounded by a 600-second limit per conversion step.
- Download the result, named after your original file with a .3mf extension.
- Load it in your slicer and check two things: the bounding box against the size you expect, and the material or filament assignment, which you will need to set by hand because the AMF's own color and material data is not in the file.
What this converter does
- Reads all three AMF packagings we see in practice: uncompressed XML, gzip, and ZIP-wrapped XML.
- Merges the vertices and triangles of every object and volume in the document into one mesh; constellations (placed copies) are not expanded.
- Recomputes triangle winding so facet normals are consistent, which avoids inverted-shell warnings in slicers on files exported with mixed winding.
- Writes a single-object 3MF with the unit set to millimeter, so slicers treat the numbers as mm without further prompting.
- Keeps the original axis orientation, so the part does not arrive lying on its back.
- Gives a clear message instead of a bad file when the upload is not really an AMF, for example a renamed .blend, an image, or a damaged ZIP.
Video Tutorial
Converting AMF to 3MF has never been easier! Quick tutorial 🚀 🔗 https://miconvert.com/en/amf-to-3mf?utm_source=youtube&utm_medium=social&utm_campaign=amf-to-3mf ⏱️ Chapters: 0:00 Let's go! 0:06 Fi
AMF to 3MF questions
Do colors and materials from the AMF survive in the 3MF?
No. Our 3MF output is geometry only: one object, one mesh, no color groups, materials, textures or print settings. Reassign filaments in your slicer after importing, and if per-part color matters, split the model into separate bodies there and color them individually.
Why is my model the wrong size in the slicer?
Because the AMF unit attribute is ignored and the coordinates are passed straight through, then labeled as millimeters. If your AMF was in centimeters, scale the imported object by 1000 percent; if it was in inches, by 2540 percent; if it was in meters, by 100000 percent. An AMF already authored in millimeters needs no change.
My AMF has several parts. Can I keep them separate?
Not through this converter: all objects and volumes are merged into one mesh and written as a single 3MF object. If you need the parts apart, export each part as its own AMF and convert them one at a time, or use the split-by-loose-parts function in your slicer on the converted file.
Does the converter repair the mesh or make it watertight?
No. There is no hole filling, no manifold repair and no decimation step. Triangle winding is normalized, and that is all. Fix non-manifold edges or gaps in a mesh tool before or after converting.
What are the batch and file size limits?
Up to 10 files per batch without an account or on a free account, 25 on Plus and 50 on Pro, each converted independently and downloaded separately; there is no combined ZIP and no way to merge several AMF files into one 3MF. Per file the ceiling is 50 MB as a guest, 100 MB free, 200 MB on Plus and 1 GB on Pro. AMF is verbose XML, so gzip-compressed AMF helps, since it counts at its compressed size.
The conversion failed. What usually causes that?
Two cases are common: a file that is not actually AMF (a renamed binary, an image, or a truncated download, which gets a message naming what was found), and a document with no usable triangles, reported as no valid 3D geometry. Re-export from the original program and check that the file opens there first.
What happens to my file after the conversion?
The upload is processed on our servers and deleted as soon as the job finishes. The converted 3MF stays available through its private download link for about four hours, then it is deleted automatically. File names, sizes and outcomes are logged for operations; the file contents are not kept.