Convert 3MF to STL (or STL to 3MF) on iPhone and iPad
Forma3D converts between 3MF and STL entirely on-device. Open the file, tap Export, pick the target format — the converted model is ready for any slicer in seconds. No uploads to web converters, no desktop.
Updated October 30, 2026 · Published by Forma3D
3MF vs STL — when to use which
| STL | 3MF | |
|---|---|---|
| Geometry | Triangles only | Triangles + topology info |
| Colors | Not supported | Per-face colors for multi-filament |
| Units | Unitless (scale often wrong) | Units embedded |
| Metadata | None | Printer profiles, materials |
| Best for | Maximum compatibility | Bambu Studio, modern slicers |
Conversion workflow
- Open — import the file from Files, Mail, AirDrop, or a download
- Inspect — rotate the model, check scale and orientation in the viewer
- Optional edits — repair, simplify, cut, or repaint before converting
- Export — choose STL or 3MF; 3MF export preserves painted face colors
- Send — share directly to your slicer workflow, Files, or MakerWorld
What you keep and lose when converting
3MF → STL: geometry survives perfectly; per-face colors and metadata are dropped (STL cannot store them). If colors matter, keep the 3MF.
STL → 3MF: geometry converts losslessly. Colors do not appear automatically — STL has none — but you can paint faces in Forma3D and export a color-ready 3MF for AMS/multi-filament setups.
Frequently asked questions
How do I convert a 3MF file to STL on iPhone?
Open the 3MF file in Forma3D from Files, Mail, or a share sheet, then tap Export and choose STL. The geometry exports as a standard STL ready for any slicer — no desktop or online converter needed.
Does converting STL to 3MF add colors?
Converting the format alone does not create colors — STL contains no color data. In Forma3D you can paint faces after import and then export 3MF with per-face color assignments for multi-filament printing.
Is 3MF or STL better for 3D printing?
3MF is the better format when your slicer supports it: it stores units, per-face colors for multi-filament printing, and printer metadata. STL stores only bare triangles — use it for maximum compatibility with older tools.
Get started
Forma3D is free to download on the App Store. Full-access features use in-app purchases — monthly, annual, or lifetime.
Next steps: edit 3MF files on iPad, paint 3MF for multi-filament printing, or STL mesh editing guide.