Free online 3MF to 3DM converter

What the 3MF format is

3MF is a ZIP-based 3D-printing format containing XML model data, triangle meshes, units, colors, materials, textures, and sometimes print-oriented metadata. Slicers such as PrusaSlicer, Ultimaker Cura, and Bambu Studio can create or export it; CAD and modeling applications may use it to exchange printable models. A 3MF package can contain several objects, arranged components, and build-plate information rather than one simple mesh.

What the 3DM format is

3DM is the native Rhino file format, based on the OpenNURBS specification. It can store NURBS curves, surfaces, solids, polygon meshes, annotations, layers, materials, and object properties. Rhino, Grasshopper, and many engineering and architectural applications use it for editable CAD models. A 3DM file can preserve a polygon mesh from 3MF, but the result remains a mesh unless you rebuild it as surfaces or solids.

How to convert 3MF to 3DM

Using Rhino

1. Install a Rhino version with 3MF import support and start a new document.
2. Choose File → Import, select model.3mf, and confirm the import options.
3. Check the document units, object scale, layer assignments, mesh colors, and the number of imported components.
4. Use Rhino inspection tools such as _What or _Check to identify invalid or damaged mesh objects.
5. Choose File → Save As, select Rhino 3D Model (.3dm), enter a filename such as model.3dm, and save.

If the 3MF import command is unavailable in the installed Rhino version, update Rhino or open the file in a 3MF-capable mesh application, export it as OBJ or STL, import that intermediate file into Rhino, and save the document as 3DM. OBJ is preferable when vertex colors or material assignments need to be carried between applications, although support varies.

You can also convert the file on the 101convert.com website for free without installing software. Review the resulting 3DM in a compatible viewer before using it for manufacturing or CAD editing.

Quality, compatibility, and limitations

Mesh-to-NURBS conversion does not happen automatically. To obtain editable CAD faces, use Rhino commands such as MeshToNurb only for simple, low-polygon meshes, or remodel the part from reference geometry. Converting a dense scan or sculpted print mesh can create thousands of separate trimmed surfaces and an impractical file.

Confirm the unit system before saving: 3MF commonly uses millimeters, while an importer may interpret unitless mesh coordinates according to document settings. Measure a known feature after import. Print settings, supports, slicer profiles, build-plate arrangements, and other manufacturing metadata may be discarded because 3DM is a modeling format. Object colors can survive as display colors, but textures, materials, and component relationships depend on the importer and may require manual repair.

For a printable result, inspect face normals, open boundaries, self-intersections, and watertightness after conversion. A 3DM file that opens successfully can still contain a non-manifold mesh unsuitable for slicing or solid-based CAD operations.