# 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.

Page: https://printpal.io/convert/3mf-to-stl
Updated: 2026-11-12
Use it: open https://printpal.io/convert/3mf-to-stl in a browser and drop a file. Free, no account, files are processed locally and never uploaded.

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.

## 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

| | Result |
|---|---|
| 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 at a glance (3D Manufacturing Format)

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.

- **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

## STL at a glance (Stereolithography (Standard Triangle Language))

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.

- **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

## Tips

- **One STL per object?** STL holds a single surface, so objects are merged. Keep them apart with [3MF to OBJ](https://printpal.io/convert/3mf-to-obj), or split later with the [3D model splitter](https://printpal.io/tools/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](https://printpal.io/tools/gcode-viewer).

## 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.

## Related

- [STL to OBJ Converter](https://printpal.io/convert/stl-to-obj)
- [STL to 3MF Converter](https://printpal.io/convert/stl-to-3mf)
- [STL to GLB Converter](https://printpal.io/convert/stl-to-glb)
- [STL to PLY Converter](https://printpal.io/convert/stl-to-ply)
- [3MF to OBJ Converter](https://printpal.io/convert/3mf-to-obj)
- [STL to USDZ Converter](https://printpal.io/convert/stl-to-usdz)
- [OBJ to STL Converter](https://printpal.io/convert/obj-to-stl)
- [STEP to STL Converter](https://printpal.io/convert/step-to-stl)
- [3D model viewer](https://printpal.io/tools/3d-model-viewer)
- [3D model converter](https://printpal.io/tools/3d-model-converter)
- [Mesh Repair](https://printpal.io/tools/mesh-repair)
- PrintPal for LLMs: https://printpal.io/llms.txt