Why convert OBJ to 3MF?
Moves a model out of general 3D software into the modern printing format, gaining real unit information that OBJ leaves ambiguous.
What is a OBJ file?
OBJ (Wavefront) is a text-based mesh format that has been the lingua franca of general 3D graphics since the late 1980s. Unlike STL it stores shared vertices rather than repeating them per triangle, supports polygons with more than three sides, and can reference materials and textures through a companion MTL file.
What is a 3MF file?
3MF (3D Manufacturing Format) is the modern replacement for STL, backed by Microsoft, Autodesk, HP and others. It is a ZIP container holding XML, and unlike STL it records real units, colours, materials and multiple objects in one file. Bambu Studio, PrusaSlicer, Orca and Cura all read and write it.
What is preserved in the conversion
The complete triangle mesh is carried across — every vertex and every face, at the original coordinates and scale, with no decimation or re-meshing. Textures and materials referenced by an MTL file are not carried across. Geometry transfers exactly and is tagged as millimetres.
Converting without uploading anything
Most online converters work by uploading your model to a server, converting it there and emailing or streaming it back. That means queues at busy times, file size caps, and a copy of your geometry sitting on hardware you do not control — a genuine problem for client work or anything under NDA.
This converter parses and writes the file inside your browser. There is no server involved, which is why there is no size limit and no waiting. Open devtools, watch the Network tab, and you will see nothing leave your machine.
Check the mesh before you print it
Conversion does not repair geometry. If the source mesh has holes or flipped faces, the converted file will have them too. The converter reports the triangle count, volume and whether the mesh is watertight as soon as it loads — and our STL viewer shows the model in 3D with a full health check if you want a closer look before committing to a print.
Frequently asked questions
How do I convert OBJ to 3MF?
Drop your OBJ file onto the converter above and press Convert. The 3MF file downloads straight away. The whole conversion runs inside your browser, so there is no upload, no queue and no account.
Is this OBJ to 3MF converter really free?
Yes — no account, no watermark, no per-file limit and no paid tier. The conversion runs on your own device, so there is no server cost to pass on to you.
Is my file uploaded anywhere?
No. The file is read by your browser and the converted result is generated locally. Nothing is transmitted — you can watch the Network tab in devtools stay silent. That matters if the part is confidential or client work.
What gets kept when converting OBJ to 3MF?
The full triangle mesh — every vertex and face, at original precision and scale. Textures and materials referenced by an MTL file are not carried across. Geometry transfers exactly and is tagged as millimetres.
Is there a file size limit?
No. Because there is no upload step, the only limit is your own device memory. Large meshes convert fine on an ordinary laptop.