Why 3MF instead of STL?

A 3MF states its unit, so a part never arrives 25.4 times too small. It stores each corner once and shares it between the triangles that meet there, where an STL repeats it for every triangle. And it is a compressed package: a 225,154-triangle STL of 10.7 MB became a 2.1 MB 3MF, and a 39,032-triangle one of 1.9 MB became 509 KB.

What size will it be?

The same millimetres as the STL, which 3D printing files use. You can also set the length of the longest side, and the part is centred on the plate and set down on it.

Does it repair the mesh?

It welds corners that sit at the same point (within 0.1 micron) into one, which turns an STL's separate triangles into one connected surface, and drops triangles that collapse to nothing. It does not fill holes or untangle intersecting parts: your slicer reports those.

Which slicers open it?

Bambu Studio, Orca Slicer, PrusaSlicer, UltiMaker Cura and every other program that reads 3MF: the file uses only the core 3MF specification. Every file written here during testing was read back with the 3MF Consortium's own library.

No. An STL holds only the shape, so the 3MF does too. Choose the filament in your slicer.

No. The STL is read and the 3MF written by your own browser, in the background of this tab. Nothing is sent to a server or stored.

Free browser tool

STL to 3MF converter.

Turn an STL into a 3MF your slicer opens at the right size: millimetres written into the file, upright on the plate, the mesh welded into one shape and the file several times smaller. It runs in your browser and your file never leaves your device.

Your model, on the stage

GLB, glTF, FBX, OBJ, STL, 3MF or a .zip · Up to 150 MB · No upload

Drop a model to convert it.

A .glb, .gltf, .fbx, .obj, .stl or .3mf, with its textures (or the whole folder). Check it in 3D, then download it in the format you need.

Your files stay in this browser tab.

Open a .glb, a .gltf with its files, an .fbx, .obj, .stl or .3mf, or a .zip of any of them. Select it together with the files it uses (a .gltf's .bin, an .obj's .mtl, textures), or drop the whole folder. A Mixamo character's FBX selected together with its animation FBXs becomes one GLB with every animation. Several models at once (an asset pack's folder or .zip) are converted or made smaller together and download as one .zip. Files are neither uploaded nor saved. Closing the model or leaving this page releases them.

Create a model in the studio →

How it works

Drop the .stl. It opens in 3D, standing upright, with its size in millimetres.
Keep 3MF for 3D printing at real size, or set the longest side, and convert.
Download the .3mf and open it in Bambu Studio, Orca, PrusaSlicer or Cura.

Have a 3MF that has to be an STL? 3MF to STL does that. Want something new to print? Almighty turns a sentence or a photo into a 3D model.

More free 3D file tools

Questions

Why 3MF instead of STL?: A 3MF states its unit, so a part never arrives 25.4 times too small. It stores each corner once and shares it between the triangles that meet there, where an STL repeats it for every triangle. And it is a compressed package: a 225,154-triangle STL of 10.7 MB became a 2.1 MB 3MF, and a 39,032-triangle one of 1.9 MB became 509 KB.
What size will it be?: The same millimetres as the STL, which 3D printing files use. You can also set the length of the longest side, and the part is centred on the plate and set down on it.
Does it repair the mesh?: It welds corners that sit at the same point (within 0.1 micron) into one, which turns an STL's separate triangles into one connected surface, and drops triangles that collapse to nothing. It does not fill holes or untangle intersecting parts: your slicer reports those.
Which slicers open it?: Bambu Studio, Orca Slicer, PrusaSlicer, UltiMaker Cura and every other program that reads 3MF: the file uses only the core 3MF specification. Every file written here during testing was read back with the 3MF Consortium's own library.
Will it have colour?: No. An STL holds only the shape, so the 3MF does too. Choose the filament in your slicer.
Is my file uploaded?: No. The STL is read and the 3MF written by your own browser, in the background of this tab. Nothing is sent to a server or stored.