Additive Manufacturing Format .amf
ISO/ASTM XML for additive manufacturing. Curved triangles, real units.
What an .amf file holds
AMF is the ISO/ASTM standard that took the first run at replacing STL: XML-based, unit-aware, with support for graded materials, colour and curved triangles that subdivide smoothly instead of faceting. It largely lost the format race to 3MF in practice, but it remains the standardised choice and turns up in research and industrial additive-manufacturing workflows.
Commonly seen in: Slic3r, PrusaSlicer, Netfabb, academic and industrial AM tooling.
| Data | Stored in AMF |
|---|---|
| Geometry | Yes |
| Materials and colour | Yes |
| Texture maps | No |
| Animation and rigs | No |
| Scene hierarchy | Yes |
| Read here | Yes |
| Written here | Yes |
Tested against a real file
The last sweep loaded test5.amf from Assimp test models with its 1 sidecar files through the viewer on this site: 4 triangles across 1 meshes and 1 materials, in 1.9 seconds. Every format's result is on the test results page, run 2026-09-08.
What we put in an .amf file we write
Geometry, per-volume material colour and the unit, written as plain XML rather than the zipped form, because half the readers that claim AMF support take only the plain one.
Convert AMF to another format
Every pairing has a page saying what survives the trip.
Convert something else to AMF
Other things to do with an .amf file
Questions about AMF
How do I open an .amf file?
Drop it into the viewer on this site and it opens in the browser, with the scene tree, the materials and the mesh statistics. Nothing is uploaded. If you want it in another program instead, convert it to GLB, which almost everything reads.
Is AMF a good format to archive in?
AMF stores geometry, materials and colour, scene hierarchy. Anything outside that list will not be in the file at all, so archive the original alongside it if the surfacing or the rig matters.
Does converting AMF lose quality?
Geometry is copied vertex for vertex, so the shape does not degrade. What gets lost is whatever the target format has no field for: convert to STL and the materials go, convert to OBJ and the animation goes. The comparison table on each converter page says exactly which.
Written up on the blog
Formats that hold the same things
Or go back to the full format reference.