[Freesurfer] inflated images

Hello all, Can some one edify me regarding how FreeSurfer is able to maintain the same basic brain geometry (hemisphere shape) when it creates an inflated file image. I would figure that some areas (because of deeper sulci) would blow up (produce more inflated surface) much differently than others thus not maintaining the basic shape. I was thinking that maybe the program just flattens it all period, but then I wouldn't really be able to explain how you can still view the respective cortical thickness data because that too must correspond with all the nooks and crannies.............

I appreciate your help, Anthony