AMF Viewer — Open AMF Files Online
Open Additive Manufacturing Format files with colour and material data, then convert them to something your slicer prefers.
Your AMF file is read and rendered entirely by your own browser. It is never uploaded to A23D, never stored, and never seen by anyone but you.
How to open an AMF file
No account, no plugin, no upload. Three steps and your model is on screen.
Drop in your file
Drag the .amf onto the viewer, or click to browse. If the model references separate material or texture files, drop the whole folder or a .zip so everything resolves.
Inspect the scene
Orbit, pan and zoom to look around. The inspector lists every mesh in the hierarchy with its triangle count, and reports the bounding box so you can sanity-check scale.
Convert or capture
Save a PNG of the viewport, or download the model converted to GLB, OBJ, STL, PLY or USDZ — all without the file leaving your browser.
What is an AMF file?
AMF — the Additive Manufacturing File Format — is an open standard published as ISO/ASTM 52915. It was the first serious attempt to replace STL, arriving around 2011, several years before the 3MF Consortium took a second run at the same problem.
An AMF file is XML, optionally compressed with zip while keeping the .amf extension. Both plain and compressed forms open here. The XML describes objects, each containing a mesh of vertices and volumes, and adds the things STL could never express.
Its most distinctive feature is curved triangles. Rather than approximating a curve with thousands of flat facets, AMF can store a triangle with curvature information at its edges, letting the printer subdivide it at the resolution the machine can actually achieve. It is an elegant idea that in practice very few tools implemented.
AMF also supports per-vertex and per-triangle colour, named materials including graded mixtures of two materials, lattice and microstructure definitions, constellations for arranging multiple objects on a build plate, and explicit units. The specification is genuinely capable.
In practice AMF lost the standards race to 3MF, which had heavier industry backing and a simpler ZIP-plus-XML container. You will still meet AMF files exported by older CAD and slicer software, and converting them to 3MF or STL is usually the pragmatic next step.
AMF at a glance
- Extension
- .amf
- Standard
- ISO/ASTM 52915
- First released
- 2011
- Encoding
- XML, optionally zipped
- Unit
- Declared in the file
- Colour
- Per-vertex and per-triangle
- Superseded by
- 3MF, in practice
What this viewer supports
- Plain and zip-compressed AMF
- Multiple objects and volumes
- Material and colour definitions
- Declared unit honoured for dimensions
- Export to GLB, OBJ, STL, PLY, USDZ
- Curved-triangle subdivision
- Lattice and microstructure definitions
AMF viewer FAQs
The questions we get asked most about opening AMF files.
Is my AMF uploaded to a server?
No. The file is parsed and rendered entirely in your browser. Nothing is transmitted to A23D and nothing is stored.
What is the difference between AMF and 3MF?
They solve the same problem — replacing STL with something that supports colour, materials and units. AMF is an ISO/ASTM standard from 2011; 3MF arrived in 2015 with broader industry backing and won adoption. If you have a choice today, 3MF has far better tool support.
Does the viewer render AMF curved triangles?
No. Curved-triangle subdivision is rendered as the flat triangles present in the file. It is a rarely implemented part of the specification, and very few exporters produce it.
My AMF will not open in my slicer. What can I do?
Load it here and convert it to STL or GLB, which every slicer and 3D tool accepts. AMF support is patchy even among printing software, which is a large part of why the format never took hold.
Does AMF store colour?
Yes, per vertex and per triangle, along with named materials. Where a file defines them they are read and displayed. Converting to STL discards that information because STL has no colour at all.
Is my compressed AMF supported?
Yes. AMF may be plain XML or zip-compressed while keeping the .amf extension, and both are handled automatically — you do not need to unzip anything first.
More format viewers
All browser-based, all free, nothing uploaded.
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