One of the important additions to the Iron Giant toon shader was "tooth" to the drawn line and a bit of "wobble" to keep the images from being too precise, giving it a more hand-drawn feeling. All images © Warner Bros. Feature Animation.

This year marks the 10th anniversary of Iron Giant (how time flies!) Two weeks ago, ASIFA hosted a reunion with director Brad Bird and various crew members, including Artistic Coordinator Scott Johnston, who provides his impressions of working on Iron Giant.

Bill Desowitz: What was your job as artistic coordinator on Iron Giant? 

Scott Johnston: My job was making sure the creative departments worked well together and worked with the producers on the overall process. In particular, I oversaw how technology was used on the show to get Brad's vision on the screen.

Brad would say what he wanted and I'd work with the crew to figure out how to do it. 

BD: Talk about coming up with the toon shader that matched the 3D to the 2D so smoothly.

SJ: The rendering "look" is only one of many things to consider when integrating CGI into a 2D film. We were making a widescreen film with a tall title character; right from the start, by design, he's an alien: he literally has trouble fitting into their world. Staging, composition and character placement had to take into account his size and the shape of the film frame. Tad Gielow's CG group developed cameras for Maya that allowed them to match the perspective of the large layouts, but re-field and pan the artwork using traditional 2D multi-plane mechanics. Sweeping 3D camera moves were saved for the climactic flight to enhance the drama of that sequence.

Interaction between the 2D and 3D components (character registration) had to be carefully orchestrated and controlled to prevent sliding that would make the elements feel separate. Steve Markowski and the other CG animators had to work carefully in both posing and timing of the Giant to maintain his scale and weight. To prevent his actions from always being smooth, his animation followed the same principles as the 2D animation and was a mixture of "1's and 2's," indicating how his action was exposed on film.