I solved the issue. The URL provided to the .modelfile should be a directory. However, this cannot be auto detected. When you append components to create url, you need to call this explicitly: folderURL.appendingPathComponent("Models/", isDirectory: true)

For those who are still keeping an eye on this. Apple's object capture is available on iOS. And it can output .obj file if the the url passed to ".modelFile" is a directory. However, any URL created is not treated as a directory by default. You need to specify it explicitly like this: newFolder.appendingPathComponent("Models/", isDirectory: true)