AR view shows black screen on second attempt to view.

[cbhojwan]

I use a segue to show the view controller that contains the ar view. Depending on the value selected on the origination view controller, different points are mapped on the ar view destination view controller. It works great the first time. then i press the back button to go back to my original screen, and after that every time i try to show the ar view it is just a black screen. Based on my debug print statements, it appears that the prarDidSetupAr method deos not get called the second time.