强制UIViewController正确布局而不将其带到屏幕上

I am having some difficulty with the following problem. I have laid out a UIViewController in Storyboard with the correct constraints. It has all the same views as the UIViewController on the screen at the present. I am using this new UIViewController for some resizing. Therefore, I would like to initialize this UIViewController, layout all the subviews, according to the constraints I have given it, and then use the UIView's frames for the primary UIViewController. Since I never need this secondary UIViewController, it is never displayed. I am having some difficulty with the following