Are the .mtl textures kept?

The .mtl is a separate file the OBJ references by name, so the conversion doesn't read it: the USDZ comes out with geometry and UVs intact but no images. If you need the material, convert to GLB with embedded textures first, then to USDZ.

How do I view it on an iPhone?

Send it over AirDrop, email or WhatsApp and tap the file: iOS opens it in Quick Look on iOS 12 and up, no app needed. The AR icon places it at real scale in the room.

Why does the model look huge or tiny?

USD measures in centimetres and most OBJs are exported in millimetres or with no defined unit. The conversion applies the standard factor; if it still looks off, rescale the OBJ first with the transform tool.

No file handy?

Convert toUSDZ

Coordinates and scale are preserved exactly as they are.

Convert OBJ to USDZ

Drop your OBJ files and download them as USDZ: free, in batch, and they never leave your device.

OBJ → USDZ: what you should know

OBJ to USDZ turns the classic 3D modelling format into the one iPhone and iPad open instantly: USDZ shows up in Quick Look with no app to install, and from there it drops into the real room through the camera.

OBJ carries geometry and texture coordinates; the material lives separately in the .mtl, with the images in loose files. Converting to USDZ brings geometry and UVs across intact — but if the OBJ relied on an external .mtl, that material isn't packaged and the model arrives with a neutral surface.

Everything runs in your browser using Three.js's USDZ exporter. The OBJ is never uploaded: the file goes in, converts, and downloads without leaving your machine.

Related conversions

STL → USDZ PLY → USDZ OBJ → STL OBJ → PLY OBJ → GLB OBJ → 3MF glTF → USDZ GLB → USDZ

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