STL viewer for iPhone and iPad
Forma3D opens STL, 3MF, and USDZ files natively on iPhone and iPad. Rotate and zoom the model, switch to wireframe or X-Ray to inspect the mesh, measure real dimensions with the ruler — then edit or export without leaving the app.
Updated October 30, 2026 · Published by Forma3D
Why you need a dedicated STL viewer on iOS
Quick Look and the Files app do not render STL files — the format predates Apple's 3D stack. Tapping a downloaded STL shows a generic document icon. Forma3D fills that gap: it renders the mesh locally on-device, offline, even for multi-million-triangle models.
What you can do beyond viewing
- Inspect — wireframe and X-Ray overlays reveal internal geometry and non-manifold issues
- Measure — ruler tool checks real-world dimensions before printing
- Scale — numeric resize in millimeters when the model is wrong-sized
- Edit — vertex, edge, and face tools if the model needs changes
- Export — re-save as STL, 3MF, or USDZ for the next step
Common STL sources that open directly
| Source | How it opens |
|---|---|
| Thingiverse / Printables / Cults3D downloads | Share sheet → Open in Forma3D |
| MakerWorld 3MF downloads | Files app → import |
| Email attachments | Tap file → share → Forma3D |
| AirDrop from Mac/PC | Lands in Files → import |
| LiDAR scans (USDZ) | Direct import in the editor |
Frequently asked questions
How do I open an STL file on iPhone?
Download Forma3D from the App Store, then open the STL from Files, Mail, AirDrop, or a browser download — choose "Open in Forma3D" from the share sheet. The model loads instantly for rotation, zoom, and measurement.
Can I measure an STL model on iPad?
Yes. Forma3D includes a ruler tool that measures real distances on the mesh — useful for checking whether a downloaded model fits your build plate before scaling or printing.
Does the iOS Files app preview STL files?
Files and Quick Look can render USDZ and some 3D formats but not STL. For STL you need a dedicated viewer — Forma3D opens STL, 3MF, and USDZ and adds measurement and editing tools on top.
Get started
Forma3D is free to download on the App Store. Full-access features use in-app purchases — monthly, annual, or lifetime.
Next steps: STL mesh editing guide, edit downloaded models on iPad, or convert between 3MF and STL.