Convert 3DM to 3MF
Convert 3DM to 3MF in your browser. The conversion runs on this page and the file never leaves your computer.
Result
Before you convert: what this keeps and what it destroys
Preserved
- The shape, to within the tessellation tolerance
- Overall dimensions and proportions
- Watertightness, where the input is watertight
- The unit, recorded in the file
- Colour
- Separate parts and their positions
Destroyed
- Exact curves and surfaces, replaced by triangles
- The feature tree and any parametric history
Why people convert 3DM to 3MF
The right target for printing a Rhino model, and the one to pick over STL every time your slicer will take it.
Both formats record their unit, so the size is carried across explicitly and nobody downstream has to assume millimetres. Object colours survive. Separate objects stay separate on the build plate instead of merging into one body, which matters for anything Rhino users typically make, since a ring plus its stone settings or a shoe sole plus its insert are natural multi-part models.
The one thing to set deliberately is the mesh. This conversion uses the render mesh saved in the file, and Rhino's defaults are chosen to look right on a monitor. If a curved surface prints visibly faceted, go back to Rhino, raise the mesh density, save, and convert again.
What you get
You get a binary 3MF file containing triangles. The reader tessellates supported surfaces or uses saved render meshes where required by the source format. Inspect curved faces at the intended output size. The triangle count depends on the model and the reader's meshing settings.
Carried across: the unit, recorded in the file, supported base or vertex colour, the supported part structure.
The conversion runs in your browser. Your file stays on your computer and is not uploaded.
What to check afterwards
- 3DM declares its unit in the file. Check the output dimensions in the receiving application, especially when its import settings can override the unit.
- Curves become facets. 3DM stores exact surfaces, so a hole is a cylinder with a radius. 3MF stores triangles, so that cylinder becomes a many-sided prism. Look at curved faces in the result at the size you intend to make the part.
If you need something this conversion cannot give you
If you need editable CAD geometry, don't convert at all. Open the 3DM file directly in FreeCAD, Fusion, Onshape or SolidWorks. Every mesh format destroys the exact surfaces, and no later conversion brings them back.
Going the other way
This site reads 3DM but does not write it. For the reverse conversion, use an application that can export 3DM.
How we know this conversion works
This pair was checked against 3 files from the test corpus on 2026-09-04. Each run parses its own output back in and compares the bounding box, the triangle count and, for closed solids, the volume against the input.
A pair that fails those checks doesn't get a page. That's why this site lists 120 conversions and not the several hundred a format-times-format grid would suggest.