3MF to STL Converter

Pull the geometry out of 3MF files and slicer projects from MakerWorld, Printables or your own Bambu Studio, as a plain STL in millimetres.

  • Files stay on your device
  • Free, no sign-up
  • Units and up axis handled
  • Batch and .zip

Drop a 3MF file to convert

One file, many, or a .zip

In: STL · STEP · IGES · OBJ · 3MF · GLB · glTF · PLY · FBX · DAE · 3DS · AMF · VRML · ZIP

Converted on your device. Nothing is uploaded.

    How to convert 3MF to STL

    1. Drop your 3MF files

      Drop .3mf files, including Bambu Studio, OrcaSlicer and PrusaSlicer projects.

    2. Check the preview

      The model appears at the size and orientation it will have. Fix the file units, up axis or size under Size, units and orientation if needed.

    3. Choose STL options

      Binary STL by default (smallest, read everywhere). Tick ASCII only if an old tool asks for text STL.

    4. Convert and download

      One file downloads straight away. A batch gives a download per file and one .zip of all of them.

    What carries over from 3MF to STL

    Worked out from what each format can store and what this converter writes. Nothing is changed silently: the preview shows the size and orientation before you download.

    Geometry Every triangle is kept at full precision.
    Color Dropped: STL cannot store color.
    Units Converted from the declared unit to millimetres, so it keeps its real size.
    Orientation Both are Z up, so it stays the right way up.
    Objects Merged into one surface: STL has no objects.

    3MF to STL: what actually happens

    A 3MF from MakerWorld, Printables or a slicer project holds more than shapes: plates, colors and print settings. 3MF to STL keeps the geometry exactly as placed on the build plate and drops the rest, which is what you need for a slicer, print service or CAD tool that only takes STL.

    Bambu Studio and OrcaSlicer projects keep each object in a separate part file inside the zip. The converter reads those, applies each object's position and rotation, and writes everything into one STL in millimetres. Multi-plate projects come out with every plate's objects side by side, as the slicer arranged them.

    3MF at a glance

    3D Manufacturing Format · .3mf

    Stores
    A zipped XML model: shared vertices, objects with transforms, a build plate
    Color
    Materials and per-triangle colors; slicers add painted filament colors
    Units
    Declared in the file, millimetres by default
    Up axis
    Z
    File size
    Compressed, usually under half of a binary STL
    Opens in
    Bambu Studio, OrcaSlicer, PrusaSlicer, Cura, Creality Print

    The 3MF Consortium (founded 2015 by Microsoft, Autodesk, HP and others) designed 3MF to replace STL for printing. Bambu Studio, OrcaSlicer and PrusaSlicer save whole projects in it: plates, painted colors and print settings alongside the meshes.

    Open 3MF files in the viewer

    STL at a glance

    Stereolithography (Standard Triangle Language) · .stl

    Stores
    Loose triangles: three corners and a normal each, binary or ASCII
    Color
    None in the standard
    Units
    None written; slicers assume millimetres
    Up axis
    Z, the slicer convention
    File size
    50 bytes per triangle in binary, about 5 times that as ASCII
    Opens in
    Every slicer, CAD tool and 3D app

    Created by 3D Systems in 1987 for the first stereolithography printers, STL is still the format every slicer and print service accepts. It describes a surface as a list of independent triangles, with no shared vertices, units, colors or scene structure.

    Open STL files in the viewer

    Tips for 3MF to STL

    One STL per object?

    STL holds a single surface, so objects are merged. Keep them apart with 3MF to OBJ, or split later with the 3D model splitter.

    Colors are lost

    STL has no color. If the 3MF is painted, print from the 3MF and use STL only where it is required.

    Sliced .gcode.3mf?

    That file is made for the printer. Preview its toolpaths in the G-code viewer.

    3MF to STL FAQ

    Can I convert a Bambu Studio 3MF project to STL?
    Yes. The converter reads the project's object files, transforms and plates. Painted colors and print settings are dropped because STL can't store them.

    Why do I get one STL instead of separate parts?
    STL is a single surface. Convert to OBJ to keep each object as its own group, or split the STL in your slicer.

    Is the STL in millimetres?
    Yes. 3MF declares its unit and the converter writes millimetres, the unit every slicer assumes for STL.

    Is the converter free? Are there limits?
    Free, with no sign-up, watermark or file count limit. Batches and files of a few hundred MB work on most laptops; the only limit is your device's memory.

    Are my files uploaded?
    No. Files are read and written by JavaScript and WebAssembly in your browser and never sent to PrintPal. The STEP and IGES reader is the only extra download, once, from a public CDN.