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3DAI
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Convert OBJ to 3MF

OBJ is the common export from Blender, ZBrush, scanning apps and AI 3D generators, but it has no unit and is usually Y up, so slicers can open it lying down or at the wrong size. 3MF records the unit and is compact. This page turns an OBJ into a print-ready 3MF on your device.

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How to use it

  1. 1

    Add the .obj

    Drop it onto the box or click to choose it, up to 100 MB. The .mtl and textures are not needed.

  2. 2

    Choose the unit

    OBJ has no unit. Pick what the numbers mean, normally millimetres, and it is written into the 3MF.

  3. 3

    Stand it upright

    OBJ is usually Y up and slicers are Z up. The model is turned upright and placed on the plate; switch either off if needed.

  4. 4

    Download the 3MF

    Open it in Bambu Studio, OrcaSlicer, PrusaSlicer, Cura or Windows 3D Builder.

What to know before you convert

  • The 3MF holds geometry only. OBJ colours, materials and textures are not converted into filament colours; assign or paint colours in your slicer.
  • All groups and objects in the OBJ are merged into one 3MF object.
  • The mesh is not repaired. Shared corners are merged and zero-area triangles are left out; holes stay and are reported in the info panel.
  • Coordinates are not rescaled. Choose the unit that matches how the OBJ was made; Blender exports are often metres.

Don't have a model?

Create one with AI from a photo, a sentence or a sketch. The generators use credits; this converter is free and stays in your browser.

Image to 3D →Turn one photo into a textured 3D model.Text to 3D →Describe an object and get a GLB.Sketch to STL →Draw it, get a printable model.

Frequently Asked Questions

Blender works in metres by default, so a 20 cm model exports as 0.2. Pick metres and the slicer shows 200 mm. Models made for printing are usually already in millimetres.
Most OBJ exporters write Y as up, while slicers treat Z as up. Leave the upright option on and the 3MF stands the right way. Turn it off if your OBJ already came from a Z-up tool.
No. Slicers read filament colours from their own project data, not from OBJ materials. Assign filaments or use the paint tool in Bambu Studio, OrcaSlicer or PrusaSlicer after opening the 3MF.
A 3MF states its unit, stores each shared corner once and is ZIP-compressed, so it is usually smaller and opens at the right size. Bambu Studio and OrcaSlicer use it as their native format.
No. The surface is kept as it is. The info panel shows whether the mesh is closed; use your slicer repair tool if it reports open edges.
No. The page reads the file and converts it inside your browser with the open-source three.js library. Nothing is sent to our servers, there is no account, and no credits are used. Closing the tab discards everything.