Convert OBJ to USDZ
OBJ to USDZ for AR Quick Look, converted in your browser. Bring the .mtl and texture files along and they come with it.
What breaks when you convert OBJ to USDZ
This is where OBJ’s missing units finally bite
OBJ stores bare numbers with no statement of what they measure, and AR Quick Look treats whatever it receives as metres. A model authored in millimetres therefore appears one thousand times too small — a sofa you have to crouch on the floor to find. Set the output units above to whatever your OBJ was actually authored in, and confirm the dimensions we report look like real-world sizes before shipping the file.
MTL predates PBR by two decades
USD Preview Surface wants base colour, metallic and roughness. MTL offers diffuse colour, specular colour and a specular exponent. There is no exact mapping between the two, so we derive roughness from the specular exponent and leave metallic at zero — which is right for wood, fabric and plaster, and wrong for anything that should look like metal. Expect to adjust metals by hand.
Bring the textures or they are gone
The MTL references its images by filename, and a browser cannot go looking for files you did not give it. Drop the .obj, the .mtl and every image together, or a .zip containing the lot. If something is missing we name it in the report rather than silently shipping an untextured model.
No normal maps in practice
MTL does have a bump map slot, but it is inconsistently used and carries no indication of whether the image is a height map or a normal map. Surface detail that was baked into one will usually not survive, so a model that relied on it for its detail will look flatter in AR than it did in your viewport.
Questions
- What do I do if my model appears tiny in AR?
- Change the output units above and convert again. The dimensions in the report tell you what the file claims before you ever open it on a phone.
- Do I need the MTL file?
- Only if you want materials. The geometry converts without it, but the result will be an untextured grey model.
- Can I drop a folder or a zip?
- A zip, yes — it is the simplest way to keep an OBJ together with its MTL and textures. You can also select all the files at once.
- How do I test the result?
- Email the .usdz to yourself and open it on an iPhone or iPad, or host it and link to it from Safari. It opens in AR Quick Look directly.