Convert OFF to 3MF
Free OFF to 3MF converter that runs in your browser. See real dimensions before you download, and get a watertight, slicer-ready file.
How to convert OFF to 3MF
- Drop your OFF file onto the converter — it opens in your browser, nothing is uploaded.
- Check the preview and the dimensions in mm; fix units or the up axis in “Units & orientation” if the size or orientation looks wrong.
- Choose 3MF as the output and click Convert. Several files download as one ZIP.
What carries over from OFF to 3MF
| OFF | 3MF | Result | |
|---|---|---|---|
| Colour / materials | No | Yes | — |
| Textures | No | No | — |
| Units stored in file | No | Yes | Written as mm |
| Separate parts | No | Yes | — |
| Usual up axis | Z | Z | Unchanged |
About OFF files
OFF, the Object File Format, was defined for Geomview, an interactive geometry viewer developed at the Geometry Center at the University of Minnesota in the 1990s. A file is plain text. The first line holds the keyword OFF, the second gives the counts of vertices, faces and edges, then each vertex appears as three coordinates and each face as a vertex count followed by index numbers. Variants add colour (COFF), normals (NOFF) or texture coordinates (STOFF) through prefixes, and colour is optional at the end of each line. The simplicity made it a favourite in computational geometry, and benchmark sets such as ModelNet used it for machine-learning research on shape classification. CGAL and libigl read and write it directly. It has no units, materials or scene structure, so it is rarely a printing format, but converting it is common.
About 3MF files
3MF was designed by the 3MF Consortium, whose members include Microsoft, Autodesk, HP, Stratasys and Prusa, as a modern replacement for STL in additive manufacturing. A .3mf file is a ZIP archive following the Open Packaging Conventions. Inside it, an XML model part holds the mesh, while other parts can hold thumbnails, textures and metadata. Unlike STL, the mesh shares vertices between triangles, which makes files smaller and keeps the surface connected. The core specification defines units, build items with placement transforms, and several objects in one file. Extensions cover materials, slices and beam lattices. Bambu Studio, OrcaSlicer and PrusaSlicer save their projects as 3MF with their own settings stored in extra files, so a project from one slicer may open in another with the geometry intact but the print profile ignored.
3D printing notes
For multi-colour and multi-part prints, 3MF is the format to use. Bambu Studio and OrcaSlicer open each part as a separate object, which lets you assign a different filament or setting to each one, and Prusa-family slicers do the same. Because the unit is stored in the file, a model does not arrive at the wrong size. Be careful with project files: a 3MF saved by Bambu Studio carries printer, plate and process settings that PrusaSlicer will not apply, and some slicers pick a different default when a model has no declared plate. MeshShift writes 3MF with several parts and keeps colours as base materials, and it reads 3MF for viewing, measuring and print checks.
Frequently asked questions
Is this OFF to 3MF converter free and private?
Yes. The conversion runs in your browser with JavaScript and WebAssembly, so your OFF file is never uploaded to a server. There is no sign-up, no watermark and no daily limit; very large files are limited only by your device's memory.
What is an OFF file used for?
OFF is a simple mesh format used mainly in geometry processing and machine-learning research. Datasets like ModelNet ship as OFF because the format is easy to parse. It is a plain text list of vertices and faces.
Is 3MF better than STL for 3D printing?
For most modern slicers, yes. 3MF records units, supports colours and several objects, and compresses well, while STL has none of those. STL remains the safer choice when a tool, a resin printer or a print service only advertises STL support.