piemonte / obj2usdz

🦖 obj2usdz, convert .OBJ files to .USDZ on iOS

obj2usdz

Create .USDZ files from iOS itself in Swift.

Note

Since WWDC19, it's now possible to write usdz files natively using SceneKit. (thanks @cpheinrich)

This repo shared an older technique prior to it's the current recommended method:

import SceneKit
import ModelIO

let asset = MDLAsset(url: objPath)
let scene = SCNScene(mdlAsset: asset)
scene.write(to: <your-usdz-file-path>, delegate: nil)

• Recommended at WWDC19

Previous Technique

With the introduction of the USDZ format and iOS 12, Apple provided guidance only for creating .usdz files using their macOS commandline tool:

xcrun usdz_converter Tyrannosaurus.obj Tyrannosaurus.usdz 
-g TyrannosaurusMesh
-color_map Tyrannosaurus_Color.png
-metallic_map Tyrannosaurus_Metallic.png
-roughness_map Tyrannosaurus_Roughness.png
-normal_map .  Tyrannosaurus_Normal.png
-emissive_map  Tyrannosaurus_Emissive.png

Exporting to .USDZ

Copy the MDLAsset+usdz.swift file into your Xcode project and create .USDZ in the following way:

let objAsset = MDLAsset(url: objUrl)

let destinationFileUrl = URL(fileURLWithPath: "path/Scene.usdz")
objAsset.exportToUSDZ(destinationFileUrl: destinationFileUrl)

Resources

• USDZ Specification
• Pixar’s USD project
• scandy blog
• BlenderUSDZ
• USDPython, Python based tools for generating, validating, and creating USD files.

License

obj2usdz is available under the MIT license, see the LICENSE file for more information.

obj2usdz's Issues

How to import USDZ file

Thanks for your work. I have download your project and have already installed Xcode. But I do not know how to use Xcode. I 'd like to ask you how to export usdz files with Xcode.Thanks a lot.

Using SCNScene's native USDZ writer

In case its useful for anybody else, I wanted to call out that since the 2019 WWDC it's now possible to write USDZ files natively using SceneKit. To convert obj to USDZ you would do

import SceneKit
import ModelIO

let asset = MDLAsset(url: objPath)
let scene = SCNScene(mdlAsset: asset)
scene.write(to: <your-usdz-file-path>, delegate: nil)

This would be the recommended way to do this suggested halfway into this video: https://developer.apple.com/videos/play/wwdc2019/602/

Hope this saves people some time