Free OBJ (.obj) to 3MF (.3mf) converter — running entirely in your browser. No upload, no signup, no file limits: your files never leave your device.
STEP · IGES · BREP · STL · OBJ · PLY · GLB · glTF · 3MF · COLLADA · AMF · FBX · 3DS · OFF · LAS · PCD · XYZ · PTS
OBJ is a plain-text mesh format from the world of computer graphics. It stores vertices, normals, texture coordinates and polygon faces, and nearly every 3D application — Blender, Maya, 3ds Max, game engines, renderers — can read and write it, making it a dependable lowest common denominator for mesh exchange.
3MF is the modern replacement for STL, backed by the 3MF Consortium (Microsoft, HP, Autodesk, Prusa and others). It stores watertight meshes together with units, colors, materials and print settings in one ZIP-based file, and current slicers increasingly prefer it over STL.
| OBJ | 3MF | |
|---|---|---|
| Geometry | Polygon mesh | Watertight triangle mesh |
| Units | No | Yes, required by spec |
| Colors & materials | Via MTL sidecar | Colors & materials |
| Animations | No | No |
| Typical use | DCC tool interchange | Modern 3D printing |
Yes — free with no accounts, no watermarks and no file-size limits. Conversion runs on your own machine, so there are no server costs behind it.
No. The converter runs entirely in your browser using WebAssembly. Your .obj file never leaves your device, which makes it safe for confidential designs.
Yes — parts and assembly hierarchy are preserved where 3MF supports them, and you can optionally merge everything into a single mesh during conversion.
Yes. Every converted model opens in the built-in 3D viewer with an assembly tree, display modes and section views, so you can inspect the result first.
The OBJ importer reads the geometry file alone; an external .mtl sidecar and its texture files are not resolved, so that material detail is absent before export. The 3MF writer keeps model units, part names and one base color per mesh, but it does not write textures, advanced materials or print settings.
Which file format should you actually print from? A practical ranking of STL, OBJ, 3MF and AMF for FDM and resin printing, with free conversion tools.
Most online CAD converters upload your intellectual property to unknown servers. Learn what actually happens to uploaded files and how client-side conversion avoids the risk.