Convert 3MF to OBJ

Why convert 3MF to OBJ?

Moving a 3MF to OBJ usually means taking a print project into a 3D art tool. Blender, Maya, ZBrush, rendering software and game engines handle OBJ readily, while 3MF support is less common. The geometry transfers cleanly, and each object or part in the 3MF becomes a named object in the OBJ, so you can still select them separately. Colours stored as base materials are written to an MTL file. Slicer information stays behind: print settings, support painting, modifiers and plate layout do not exist in OBJ. 3MF stores a unit (usually millimetres) while OBJ has none, so the numbers come out in millimetres and you may need to scale by 0.001 when importing into a program that works in metres.

How to convert 3MF to OBJ

1. Drop your 3MF file onto the converter — it opens in your browser, nothing is uploaded.
2. Check the preview and the dimensions in mm; fix units or the up axis in “Units & orientation” if the size or orientation looks wrong.
3. Choose OBJ as the output and click Convert. Several files download as one ZIP.

What carries over from 3MF to OBJ

What changes

• Print settings, plate layout and slicer modifiers are not part of OBJ.
• Parts remain separate objects; colours become MTL materials.
• OBJ stores no unit; values are in millimetres from the 3MF.
• Triangles are unchanged, with shared vertices where possible.

Tips

• In Blender, import with a scale of 0.001 or set the unit scale to millimetres.
• Keep the OBJ and MTL together in one folder so colours load.
• If you only need the shape for sculpting or rendering, discard the MTL.
• Return to the 3MF master for printing after edits, or export a fresh 3MF.

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.

About OBJ files

OBJ comes from Wavefront Technologies' Advanced Visualizer software in the 1980s, and it has outlived the product. A file is plain text: lines starting with v define vertices, vt texture coordinates, vn normals, and f faces that reference those lists by index. Faces may be triangles, quads or larger polygons, and the g and o keywords group faces into named objects. Appearance is not in the OBJ at all; a line called mtllib points to a separate .mtl file that lists materials with diffuse colours and texture image names. The format is verbose, has no official unit and no scene hierarchy or animation, but it is trivial to read and write. That is why scanners, photogrammetry tools, sculpting programs and game pipelines still use it to move static meshes around.

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.

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