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.3mf3MF→.objOBJlossless

Convert 3MF to OBJ

Convert 3MF to OBJ in your browser. The conversion runs on this page and the file never leaves your computer.

Drop your .3mf file

up to 250 MB · .3mf

Free, and it opens in this tab. Nothing is uploaded, and there's no account to make.

Runs locally · nothing uploaded

Before you convert: what this keeps and what it destroys

Preserved

  • The geometry, triangle for triangle
  • Overall dimensions and proportions
  • Watertightness, where the input is watertight
  • Colour
  • Separate parts and their positions

Destroyed

  • A recorded unit: OBJ stores none
  • Colour
  • The separation between parts, merged into one body

↺ the reverse: OBJ → 3MF · about .3mf · about .obj · just view it instead

Why people convert 3MF to OBJ

Taking a print file into a renderer or an older mesh tool. OBJ's universality is the whole reason, because outside slicers almost nothing reads 3MF.

Object names carry over. Two things do not, and both are things 3MF was specifically designed to have. The unit declaration disappears, since OBJ records none, so the numbers land as bare millimetre-magnitude values. Colour disappears too, because the OBJ here is written without a .mtl library beside it.

If either matters more than compatibility, GLB keeps both and PLY keeps colour per vertex.

What you get

You get a plain-text OBJ file you can open in an editor containing the same triangles the 3MF file described. No geometry is added, removed or approximated: mesh-to-mesh conversion is a change of container, and this site's tests check that the triangle count comes out identical.

Carried across: object names, with positions applied to the geometry.

Not carried across by this conversion: a recorded unit, colour.

The conversion runs in your browser. Your file stays on your computer and is not uploaded.

What to check afterwards

  • 3MF declares its unit in the file. Check the output dimensions in the receiving application, especially when its import settings can override the unit.
  • The output keeps supported geometry and object names. The writer applies part transforms to the coordinates, without retaining the original transform hierarchy. It does not write material colours, texture coordinates or a companion material file.

If you need something this conversion cannot give you

If the unit has to be unambiguous, convert to 3MF instead. It records the unit in the file, so nobody downstream has to assume millimetres and nobody has to scale by 25.4 after the fact.

Going the other way

Convert OBJ back to 3MF. The reverse conversion also works with mesh geometry. It does not reconstruct exact CAD surfaces. Material data and part structure lost in either direction cannot be restored by converting back. Keep the original file for later edits.

How we know this conversion works

This pair was checked against 13 files from the test corpus on 2026-09-04. Each run parses its own output back in and compares the bounding box, the triangle count and, for closed solids, the volume against the input.

A pair that fails those checks doesn't get a page. That's why this site lists 120 conversions and not the several hundred a format-times-format grid would suggest.