3D Manufacturing Format .3mf
Modern 3D-printing format. Colour, units and build plate included.
What a .3mf file holds
3MF is what STL should have been. Built by the 3MF Consortium as a zipped XML package, it records units, colours, materials, per-object print settings and the arrangement on the build plate, and it defines what a valid manifold mesh is so slicers stop guessing. Bambu Studio, PrusaSlicer and Cura all treat it as a first-class project format.
Commonly seen in: Bambu Studio, PrusaSlicer, Cura, Windows 3D Builder, Fusion 360.
| Data | Stored in 3MF |
|---|---|
| Geometry | Yes |
| Materials and colour | Yes |
| Texture maps | Yes |
| Animation and rigs | No |
| Scene hierarchy | Yes |
| Read here | Yes |
| Written here | Yes |
Tested against a real file
The last sweep loaded cube_gears.3mf from three.js examples through the viewer on this site: 25,692 triangles across 17 meshes and 17 materials, in 2.0 seconds. Every format's result is on the test results page, run 2026-09-08.
Convert 3MF to another format
Every pairing has a page saying what survives the trip.
Convert something else to 3MF
Other things to do with a .3mf file
Questions about 3MF
How do I open a .3mf 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 3MF a good format to archive in?
3MF stores geometry, materials and colour, texture maps, 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 3MF 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.