How to view arobject extension format exported from Apple ARKit 2.0 Scanning 3D objects App?

Question

I am getting my hands dirty with the new ARKit2 object scanning and recognition tool that was part of WWDC 2018 Demos. All details can be found here.

https://developer.apple.com/documentation/arkit/scanning_and_detecting_3d_objects

Once the scanning process is completed this app exports the scanned object file as arobject to iOS files app.

I cannot find answers on apple sites or developer forums on the following:

1. How to display the arobject files? Clearly the files app cannot understand the arobjects file extension.
2. How can we store the files as usdz format from scanner app to allow for the new quick look feature to be used with iOS file app (as shared in the WWCD 2018 Demos)?

Answer 1

As noted in Apple's Scanning and Detecting 3D Objects doc:

An ARReferenceObject contains only the spatial feature information needed for ARKit to recognize the real-world object, and is not a displayable 3D reconstruction of that object.

An .arobject file is simply an instance of the ARReferenceObject class in serialized filesystem form, so this advice applies to both.

There's nothing displayable about a reference object — it's opaque data representing whatever magic ARKit remembers upon scanning an object that helps it recognize that object later. It's not equivalent to USDZ, SCN, OBJ, ABC, DAE, FBX, STL or other 3D asset formats — those describe polygon meshes, shader features, and other attributes relevant to rendering realistic virtual objects and/or 3D printing.

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One thing you can do with an ARReferenceObject is give it a 2D preview image when saving one — see export(to:previewImage:). This gets displayed in Xcode, but it doesn't look like QuickLook in macOS Finder or iOS Files know how to display it, and it's not documented how another app is supposed to read that from the file. (Those would be good things to file bugs with Apple about.)