I'm trying to get my app to recognize .obj files for importing.
I've tried to follow the instructions in this WWDC video.
I've tried specifying as both an Imported UTI, and an Exported UTI. Neither causes the file to be openable in UIDocumentBrowserViewController (the document icon is grayed). I don't understand how my native document format is openable in the browser either. I've tried deleting and reinstalling the app from the device.
What am I missing? Why isn't this simple?
Here's what I've got:

