Every project has its own challenges, but the most challenging piece had to be The Incredible Hulk (2008). Whenever you design a character that's so well known, you have to be sensitive to the fan base, while making something that works for the film, and feels fresh. It took hundreds of designs to get the final version.
For the Hulk, I started in ZBrush with a base human I had made, and began to change the proportions of the body until I felt it was close to a Hulk-like body. From there, it was making many variations until we got something that was working for the director.
Then I focused on the head. This was the most time-consuming part - mainly because this is where the character really is. The face, the eyes - it's what makes the Hulk, the Hulk. This is where the personality of the character comes through.
Focusing on the Hulk was a process of finding the right look from the structure of the head and face to the length of hair to the exact shade of his skin. Then I also had to incorporate how much of the actor we wanted to see within these designs. I must have done hundreds of versions.
I started with modelling in ZBrush; would bring it into to Softimage to do my render passes; then in Photoshop I'd composite them together and do my tweaks. I would add layers of photos for pores, wrinkles, hair, etc, to help contribute to the realism. After a lot of hard work, we finally found our Hulk.
Aaron Sims is one of the most innovative and versatile concept artists working in films today. He set up his own company in 2005 and has contributed designs for, among other movies, X-Men: First Class, Clash of the Titans and The Amazing Spider-Man.
This article first appeared in 3D World magazine issue 173.