USDZ to STL Converter
FileFlip converts USDZ to STL entirely inside your browser, using Assimp compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a USDZ file to STL?#
- Drop your USDZ file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to STL and the conversion starts on its own. FileFlip downloads 11.2 MB of WebAssembly the first time and nothing after that, then runs Assimp on your own machine.
- Save the STL file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting USDZ to STL lose quality?#
Not in the sense of pixels or samples. Converting USDZ to STL rebuilds the file in STL's own model rather than re-encoding it, so everything STL can represent comes through exactly and anything it cannot has to be dropped. Expect the geometry to be exact, and anything the target has no place for, such as a rig, to be left behind.
Is it safe to convert USDZ files online?#
Yes, because nothing is uploaded. FileFlip converts USDZ files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What USDZ to STL actually does to the file#
Converting USDZ to STL runs on Assimp, downloads 11.2 MB of WebAssembly the first time and nothing after that, rebuilds the file in the target's own model, and drops materials, textures and skeleton and animation.
| Engine | Assimp |
|---|---|
| Conversion path | One step: USDZ → STL |
| Downloaded to your browser | 11.2 MB, once, then cached by your browser |
| Quality | Rebuilt in the target's model |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Materials | Dropped | The target format has nowhere to put it. |
| Textures | Dropped | The target format has nowhere to put it. |
| Skeleton and animation | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- the target stores triangles and nothing else, so materials, colours, and texture coordinates have nowhere to go
- if the source carries a skeleton or animation, this target has no place to store it
What is a USDZ file?#
A USDZ file is a zero-compression ZIP archive holding one or more USD layers together with their textures, audio and other referenced assets, packaged as the single file Apple's AR Quick Look expects.
Use USDZ when a model needs to open in AR Quick Look on an iPhone or iPad, or travel as one self-contained file with its textures attached.
Convert away from USDZ when the model is headed into a DCC tool or pipeline that expects an unpacked USD layer rather than a zip package.
What is an STL file?#
An STL file is a triangle mesh created by 3D Systems in 1987 for its stereolithography 3D printers, storing nothing but a flat list of triangle facets and their normals, with no colour, material or unit of measurement attached.
Use STL when the only destination is a 3D printer's slicer, which is all the format was designed to feed.
Convert STL to 3MF when colour, material or unit information needs to travel with the geometry, since STL has nowhere to put any of it.
USDZ to STL questions people ask#
What opens a USDZ file?
On a Mac or iPhone, USDZ opens straight in Quick Look from the Finder, Safari, Messages or Mail with no separate app needed. Blender and Adobe Aero also read USDZ on any platform if you need to edit rather than just view it.
Why is USDZ used for AR on iPhone?
Apple built USDZ specifically as the file AR Quick Look expects, so tapping a USDZ link in Safari or Messages drops straight into an augmented reality view with no app install. It packages the model's textures and audio in the same file, so there's nothing else to fetch.
Is USDZ compressed?
No. A USDZ file is a ZIP archive stored with zero compression, which makes it larger than a normally compressed ZIP but lets the assets inside be read directly from the file without unzipping first.
Can I edit a USDZ file?
Not directly as a package. Editing means unpacking the USD layer and its assets, making changes in a tool like Blender or Maya, and re-exporting to USDZ.