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3DAI
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Convert 3MF to STL in Your Browser

3MF is the project format of modern slicers and model sites such as MakerWorld and Printables. Some tools, older slicers and CAD programs still only accept STL. This page reads the 3MF package on your device, applies each object's position and units, and gives you STL files.

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How to use it

  1. 1

    Add your .3mf

    Drop the file onto the box or click to choose it. Slicer projects with several plates and objects are supported.

  2. 2

    Check what was found

    All objects on the build plate are shown in their arranged positions, with the total size in millimetres.

  3. 3

    Merge or split

    Download one STL with everything, or tick "one STL per object" to get a ZIP with a separate STL for each part.

  4. 4

    Load into your tool

    Each STL keeps the same placement, so split parts line up again when you load them together.

What to know before you convert

  • STL is geometry only. Filament colours, painted areas, plate layout, supports and all print settings in the 3MF are not carried over.
  • Sizes are converted to millimetres from the unit the 3MF declares (micron, millimetre, centimetre, inch, foot or metre).
  • Every object placed on the build plate is included, in the position it was arranged in. Modifier meshes and other non-printing helper objects are skipped.
  • Encrypted 3MF files and the beam-lattice and slice extensions are not supported. Those are rare outside industrial printers.
  • The mesh is not repaired. If the 3MF had open edges or overlapping parts, the STL will too; the info panel shows whether it is watertight.

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

STL stores only triangles. Multi-colour information in a 3MF, such as filament assignments or painted faces, has nowhere to go. Keep the 3MF for colour printing and use the STL for tools that need plain geometry.
Yes. Their projects store each object in its own file inside the 3MF package and point to it from the build plate. The converter follows those references, so every object comes out with the right shape and position.
Yes. When the 3MF has more than one object, tick "One STL per object". You get a ZIP with one STL per object, each named after the object and placed where it sat on the plate.
Yes. A 3MF declares its unit, and the converter turns it into millimetres, which is what slicers expect from an STL. A model saved in inches is multiplied by 25.4.
A 3MF is a ZIP-compressed archive that shares corner points between triangles. A binary STL stores three full corners for every triangle and is not compressed, so it is often several times larger.
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.