Format Guide
The modern replacement for STL — full color, material, and print settings in a single compact file.
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| Extension | .3mf |
|---|---|
| Full name | 3D Manufacturing Format |
| Container | ZIP archive with XML data |
| Geometry type | Triangle mesh + metadata |
| Open standard | Yes (3MF Consortium) |
| Supports color | Yes — per-vertex, per-triangle, per-object |
| Supports materials | Yes — multiple materials per model |
| Supports assemblies | Yes — components and constellations |
3MF (3D Manufacturing Format) was developed by the 3MF Consortium (Microsoft, Autodesk, HP, Ultimaker, and others) in 2015 as a modern replacement for STL. A 3MF file is a ZIP archive containing XML geometry data plus optional color, material, texture, support structure, and print setting metadata. Unlike STL, 3MF supports full-color models, multi-material assemblies, per-triangle color, and structured metadata. File sizes are significantly smaller than ASCII STL. PrusaSlicer, Bambu Studio, Cura, and Chitubox all support 3MF natively.
For multi-color or multi-material FDM printers (Bambu Lab AMS, Prusa MMU), 3MF carries per-part color and material assignments that STL cannot express.
HP Multi Jet Fusion and other powder-bed systems use 3MF to carry full-color and material data natively. The format is specifically designed for production AM workflows.
3MF files can bundle slicer profiles and print settings, allowing print farms to reproduce exact configurations without manual re-configuration per job.
PrusaSlicer, Bambu Studio, Cura, Chitubox, Windows 3D Builder, Autodesk Fusion 360, SolidWorks 2024+, and Materialise Magics.
Commonly converted from STEP or STL for additive manufacturing, or to STL for compatibility with legacy slicers that do not yet support 3MF.
3D CAD Converter turns STL meshes, OBJ models and STEP solids into print-ready 3MF files in three steps — one model or a whole folder at a time.
Add your source files
Drag an STL, OBJ or STEP file (or an entire folder) into 3D CAD Converter. Mixed formats in the same batch are fine.
Choose 3MF as the output
Select 3MF as the target format. For STEP solids, set the tessellation quality so curved surfaces are approximated as finely as you need.
Convert and open in your slicer
Run the conversion and open the resulting .3mf directly in PrusaSlicer, Bambu Studio, Cura or Windows 3D Builder — geometry, units and color travel inside one file.
Prefer the command line? The bundled cadconvert CLI converts to 3MF with a single command:
Add --tessellation 0.1 to control mesh fidelity when the source is a STEP solid. Output 3MF files are watertight and ready to slice.
STL stores only raw triangles — no color, no materials, no units, no print settings. A 3MF file packs all of that into a single, compact, watertight ZIP-and-XML package: per-part color, multiple materials, embedded units (so a model is never mistaken for the wrong scale) and even slicer profiles. That is why Bambu Lab, Prusa and HP build their multi-color and production workflows around 3MF.
3MF is also smaller than ASCII STL and far less ambiguous: where STL leaves orientation and scale to guesswork, 3MF declares them explicitly, so the part that leaves your CAD tool is the part that prints. For single-color hobby prints STL is still perfectly fine, but for anything with color, multiple materials or shared print settings, 3MF is the better container.
Compare the alternatives in depth: STL, OBJ. Read STL vs OBJ vs 3MF for 3D printing.
Some legacy or device-bundled slicers predate 3MF support. If your slicer rejects a .3mf, convert it back to STL with 3D CAD Converter — geometry is preserved, you only lose color and metadata that the old slicer could not use anyway.
STL carries no color, so converting 3MF to STL and back drops every material assignment. Keep the original 3MF as your master and only export STL copies for tools that need them.
3MF embeds units, but a mesh built in inches and exported without unit info can import at the wrong size. Set --units in (or the equivalent in the desktop app) so the 3MF declares the correct scale.
PrusaSlicer, Bambu Studio, Cura, Fusion 360 and SolidWorks 2024+ read 3MF well, but some CAD viewers still do not. When in doubt, keep an STL or OBJ copy alongside the 3MF for maximum compatibility.
A .3mf file is a 3D Manufacturing Format model — an open standard from the 3MF Consortium. It is a ZIP archive holding XML geometry plus optional color, material, units and print-setting data in one watertight package, designed as a richer replacement for STL.
On Windows, open it with the built-in 3D Builder or Paint 3D. You can also open it in Fusion 360 or SolidWorks 2024+, or convert it to STL or OBJ with 3D CAD Converter to view it in any mesh tool. Since a 3MF is a ZIP archive, you can even rename it to .zip and inspect the XML inside.
For modern 3D printing, yes. 3MF stores color, materials, units and print settings that STL cannot, in a single smaller, always-watertight file. STL remains handy for legacy slicers, but 3MF is recommended for multi-color, multi-material and print-farm workflows.
Yes. 3D CAD Converter offers a free trial that converts STL, OBJ and STEP to 3MF, including whole folders in batch. Run cadconvert convert -i model.stl -o model.3mf from the CLI, or use the desktop app and pick 3MF as the output.
3MF fully supports color, but plain STL stores none — so an STL to 3MF conversion produces geometry only. To keep color, convert from a colored OBJ or a STEP file with AP214/AP242 color; 3D CAD Converter preserves color whenever the source format provides it.