The suit design process involved a lot of ideation before settling down and refining the final Mk3 design. Below are some of the sketches from that exploration. This was kind of a shotgun approach, trying out a lot of different aesthetics and rendering techniques.
This first one was an attempt to try to update the color breakup of the original red and gold suit. This one is a lot more of a bruiser than the final production model, and I was exploring some form ideas to try to give the impression of solidity to the sheet metal, shearing off organic forms to create flat surfaces defined by strong edges. This was an approach that we ended up adapting to the final design in areas like the forearms & legs.
The next one came from the concept of "wearable ordinance" as an alternative to the more streamlined "wearable aircraft" approach that had emerged from Adi's original sketch. I referenced modern tank ablative armor, as well as medieval and roman armor. It had an interesting aesthetic, but ultimately wasn't iconic enough.
This was an attempt at a more modular and organic approach, that would have used Electroactive Polymer Actuators (real-life artificial muscles that are being developed by JPL and NASA, using plastics that contract or expand when current is run through them.) Jon noted that the audience expectation would be more mechanical, with miniaturized pistons, actuators & servos to connect with the metaphor of Iron Man. I think he went in the right direction.
A more streamlined and athletic approach that tried for thicker overlaps between plates. Jon felt that this was too much of a "swimmer's body", rather than the more powerful boxer's build he was looking for. As I think we all expected from the beginning, an evolution of Adi's wearable airplane design was ultimately the way to go.
I also spent a lot of time in this phase working on a Mk 4 suit which would be a militarized version (can you say War Machine, anyone?) that was ultimately cut from the script. With any luck it will turn up in the sequel!