While actor Henry Cavill worked his ass off getting into incredible shape for Zack Snyder's upcoming "Man of Steel," all superhero suits used in movies have some level of careful layering, padding and sculpting.
This is done to both showcase the already impressive physique underneath, and to protect the actor during filming of the project's rough and tumble action scenes.
Actor Mackenzie Gray, whose role in the film is 'top secret' though has been speculated to be playing Lex Luthor, has spoken with JTM Games and revealed some details about the Superman costume:
"Amount of detail on Superman is unbelievable. Superman’s costume, is a three-layer costume; there’s a body-skin layer and then there’s a muscle layer that was molded to Henry’s muscles – it’s a silver, metallic rubber – and then over that is a mesh skin so whenever he turns into light it looks like he’s made of steel....It’s just incredible, the design of the film is fantastic."
Source: JTM Games