CATransform3DMakeRotation hides half the UIView during animation
For the record, the answer was in my comment
imageView.layer.zPosition = -400;Alternatively you could do
myView.layer.zPosition = 400; // or some number greater than width/2It looks like part of the rotating view is occluded by the background view. Since it rotates around its center point, part of it passes into negative-z space, so is behind the background.
So from
------- imageView------- myViewto
/ myView /------- imageView / /