nozzlefox

OBJ3MF

OBJ to 3MF converter

Turn an OBJ and its MTL into a 3MF that keeps the colours and the parts, at the right size for printing.

  • Nothing uploaded
  • No sign-up
  • Free, no limits

Drop your OBJ file here (and its .mtl)

or paste it, or pick it from your device

.obj · .mtl

  1. Drop your OBJ file
  2. Check it in 3D
  3. Download 3MF

Good to know

How to convert OBJ to 3MF with colours

  1. Drop the OBJ together with its .mtl file: the MTL holds the colours. (You can add the MTL after the OBJ, too.) Nothing is uploaded.
  2. Check the size and which way is up. OBJ files have no unit, so the unit is guessed from the numbers; change it if the size looks wrong. Models from Blender and game engines are usually Y-up and get stood upright.
  3. Download the 3MF. Each object stays a separate part, in its colour.

Why 3MF instead of STL

An STL has no colours, no units and no separate parts. A 3MF keeps all three, so Bambu Studio, PrusaSlicer and OrcaSlicer open the model in its colours, each part ready to be given a filament.

  • Colours from the MTL (each material's diffuse colour) and colours stored per vertex are both kept.
  • Image textures aren't: a 3MF for printing holds solid colours, not pictures wrapped round the model.

To print each colour as its own file instead (for Cura, or one STL per extruder), use Split by colour. For a plain single-colour STL, use OBJ to STL.

Questions

How do I convert OBJ to 3MF and keep the colours?

Drop the OBJ and its .mtl file into the tool on this page together, then click Download 3MF. Material colours and separate objects are kept.

Why are the colours missing?

The colours live in the .mtl file next to the OBJ. Drop both files; if the MTL refers to image textures only, there are no solid colours to keep.

Will it be the right size?

OBJ has no unit, so the tool guesses from the numbers and shows the size. Change the unit if it's wrong before downloading.

Is it free?

Yes. It runs in your browser, nothing is uploaded, and there's no sign-up.