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3DAI
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Convert STL to 3MF

3MF is the modern print format: it records the unit of the model, stores each corner point once and is compressed. Modern slicers open it natively and some print farms and model sites prefer it. This page turns an STL into a clean 3MF on your device.

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How to use it

  1. 1

    Add the .stl

    Drop it onto the box or click to choose it. Binary and ASCII STL both work, up to 100 MB.

  2. 2

    Choose the unit

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

  3. 3

    Place it on the plate

    The model can be dropped onto the build plate so it starts at height zero in the slicer.

  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. No colours, print settings, supports or plates are added; set those in your slicer and save the project there.
  • The mesh is not repaired. Corner points that are the same are merged, and triangles that collapse to a line or a point are left out; the number is shown if any were.
  • The model is written as one object. Several separate shells in one STL stay together in that object.
  • The coordinates are not rescaled. Choose the unit that matches how the STL was made; the size readout shows the result.

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

A 3MF states its unit, so the model will not open 25 times too small or too big. It stores each shared corner once and is ZIP-compressed, which often makes it several times smaller than the STL. Slicers also use 3MF to save the full project later.
Yes. The file follows the 3MF core specification with a standard package layout, so Bambu Studio, OrcaSlicer, PrusaSlicer, Cura and Windows 3D Builder open it as a normal model.
No. The surface is kept as it is. Duplicate corner points are joined, which is how 3MF stores meshes, and zero-area triangles are left out. Holes and flipped faces stay; use your slicer repair tool if the info panel shows open edges.
Millimetres for almost every STL made for printing. Choose inches if the model was designed in inches and opens tiny as an STL. The unit is written into the 3MF, and the slicer converts it for you.
Not on this page. Open the 3MF in your slicer to assign filaments, paint it or add more parts, then save the project from there.
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.