First off all look at apple referce, it has some properties that might help you in block rotation: https://developer.apple.com/library/ios/documentation/uikit/reference/UIViewController_Class/Reference/Reference.html
In my point of view something like this may help you, just add method in .m file and implement correctly
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
[_arViewController.view setFrame:self.view.frame];
}