How to convert OBJ to 3MF
- Drop your .obj file into the box above, or click Choose file.
- Check the 3D preview, size and triangle count.
- Make sure 3MF is selected as the output format. Adjust scale or up-axis if needed.
- Click Download. The .3mf file is created instantly on your device.
Why convert OBJ to 3MF?
3MF stores units explicitly and is the native format of modern slicers, so it removes guessing about scale.
What changes in the conversion
- Textures are dropped. 3MF cannot store image textures (colours may be kept).
- Units. 3MF is defined in metres. Large models (in millimetres) are scaled ×0.001 automatically so they appear at real size.
- Up-axis. OBJ is Y-up while 3MF is usually Z-up; the model is rotated so it stands the right way up. Untick "Convert up-axis" to keep the raw coordinates.
- Geometry is preserved. Every triangle, with all object transforms applied, ends up in the new file.
OBJ vs 3MF
| OBJ | 3MF | |
|---|---|---|
| Full name | Wavefront OBJ | 3D Manufacturing Format |
| Stores | geometry, normals and UV coordinates (materials live in a separate .mtl file) | geometry, units, colours and (slicer-specific) print settings |
| Colour | No | Yes |
| Textures | Yes | No |
| Units | none | stored in the file (usually millimetres) |
| Exact CAD geometry | No | No |
About the formats
OBJ (Wavefront OBJ) was introduced by Wavefront Technologies for its Advanced Visualizer software. It is a plain-text mesh format that stores vertices, faces, normals and texture coordinates, with materials in a separate MTL file. It is widely used to move models between 3D modelling programs such as Blender, Maya, 3ds Max and ZBrush.
3MF (3D Manufacturing Format) was developed by the 3MF Consortium (Microsoft, HP, Autodesk, Ultimaker and others) since 2015. It is a zipped XML package that stores meshes together with units, colours, materials and print settings. It is the modern replacement for STL in 3D printing – PrusaSlicer, Bambu Studio and Cura save projects as 3MF.
Frequently asked questions
Is this converter free?
Yes. You can convert OBJ to 3MF for free – up to 3 conversions a day, with no sign-up and no watermark. If you need more, Pro gives you unlimited conversions and batch conversion (free for 7 days).
Are my files uploaded to a server?
No. The conversion runs entirely in your browser using WebAssembly and JavaScript. Your model never leaves your computer, which also makes it safe for confidential parts and patient data.
Is there a file size limit?
There is no fixed limit. Files of a few hundred megabytes work on a typical laptop; the practical limit is your device's memory.