tigtools

3MF to STL

Choose a .3mf file from a slicer or CAD program to get STL files for any 3D printing tool. Nothing is uploaded.

Runs in your browser No sign-up

or drop it here. The file stays on your device.

How to use it

  1. Choose or drop a .3mf file.
  2. Check the list of objects and their sizes.
  3. Choose one merged STL or one STL per object, and binary or ASCII.
  4. Download the STL or the ZIP.

How it works

A 3MF file is a ZIP archive. The tool opens it with JSZip, finds the main model through _rels/.rels (normally 3D/3dmodel.model) and reads the XML: mesh objects (vertices and triangles), component objects that reference other objects, also in other .model files of the archive as Bambu Studio and PrusaSlicer write them, and the build items that place objects on the plate. Component and build transforms are applied, so every object appears where it was placed.

Units are converted to millimetres (micron, centimetre, inch, foot and metre are supported), because STL has no unit and slicers assume millimetres. Binary STL is compact; ASCII STL is readable text but several times larger. Normals are computed from the triangle winding. If the 3MF has no build items, every model object is exported once.

Limits: colours, materials, textures, beam lattices, slice stacks and slicer settings are not converted, because STL cannot store them. Very large files need a lot of memory in the browser.

Examples

Plate from Bambu Studio

A 3MF with four parts on one plate becomes one merged STL in the same arrangement, or four STLs in a ZIP when you choose one file per object.

Model downloaded as 3MF

A model from a repository that only offers 3MF can be converted to binary STL for an older slicer or a CAD program that does not read 3MF.

Frequently asked questions

Are the objects in the right position?

Yes. The transforms of build items and components are applied, so the merged STL matches the arrangement in the 3MF.

Why is my STL in millimetres when the 3MF used inches?

STL files carry no unit and almost every slicer reads them as millimetres, so the tool converts the coordinates. A 1 inch cube becomes a 25.4 mm cube.

Are colours and multi-material settings kept?

No. STL can only store triangles. Keep the 3MF if you need colours, materials or print settings.

Binary or ASCII?

Choose binary unless a program specifically needs ASCII. Binary files are about five times smaller and load faster.

Privacy

The 3MF file is unzipped and converted in your browser. Nothing is uploaded or stored, and only an anonymous event that the tool was used is counted.