Iron Man's HUD is one of the several very cool aspects of the films. It's a fun and inventive way of seeing Tony Stark inside his armor. Here's a great behind the scenes video posted by John Likens that breaks down the visual effects done by Cantina Creative to create the HUD for Iron Man 3. Here's an explanation that came along with the video:
Marvel tasked us with designing all the elaborate 3D head-up displays (HUDs) – a virtual graphical interface that Iron Man sees from within the helmet environment of his armored suits that communicate essential data and statistics ranging from his physical condition to weapon and navigational diagnostics – While putting strong emphasis on the new ultra-high-tech Mark 42 suit, we also delivered upgraded HUDs to match the new suits seen in the film. It was great fun.
All of the 3D elements, including a miniature version of the suit and the holographic helmet, were generated and rendered from CINEMA 4D. These graphics had true 3D depth, which heightened the stereo viewing experience as well as the interactive light qualities that are both photo-real and immersive.
This is a process montage that was created to give some insight into the development and design thinking stages of the work I was specifically involved with on the film.
This is a great video with lots of cool and interesting stuff to see.