Scott Johnston Talks <em>Iron Giant</em> 10th Anniversary

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 [1] 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 [2] 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.

Using a toon shader wasn't novel on The Iron Giant. Tad and I had both written them in the early '90s prior to coming to Warner Bros. Mine was initially for Aladdin [3]and Lion King [4], and Tad's, in Florida, for short films and what was eventually used on Mulan [5]. What Tad's CG team did on Iron Giant was to do a much better job of integrating the technology into the production pipeline. For example, making it work directly with the tools that were being used by the back-end of production. This included Andy King's work exporting geometry data from Maya into RenderMan [6], the toon shading and image processing by Brian Gardner and the format conversion for printing 2D animation reference and integration into Animo (the 2D system) for ink-and-paint by Brett Achorn, Aaron Thompson and Babak Forutanpour. One of the important visual touches Brian added to the system was some "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.

One of Johnston's favorite memories was an early crew screening that boosted morale: When the lights came up, the crew was newly energized.

BD: Any favorite moments come to mind?

SJ: One of my favorite memories was a crew screening early on. The IG team was in a different building than the animation crew, who were finishing The Quest for Camelot [7]. Quest had been a very difficult production and we knew there were procedural things to change, and morale and confidence to boost. Brad had a rough version of the film up on reels and we brought the crew in for a screening. The crew looked drawn and tired filing in. Brad introduced the film, made standard disclaimers about how rough everything was, asked for feedback and showed the film. When the lights came up, the crew was newly energized. They knew what they saw wasn't perfect, but it was a solid movie--the potential was there and it looked like a lot of fun to make. The buzz in the room was a huge change to how people were feeling at the beginning of the day.

Because of the limited budget, it was important to spend money wisely early on rather than waste it in production. This meant more planning in story, where a lot of the staging was worked out, and in "Workbook," a process that isn't used very often anymore. Prior to drawing the layouts, the layout department (with some people borrowed from story) created workbooks for each sequence. These are like blueprints, pulling information from the storyboards and thumb-nailing layout ideas and annotating the separation of elements for layout. Locations were roughed out, staging and cinematography plans were clarified and initial lighting directions and contrasts were chosen.

In the workbook turnover session, with all the department supervisors present, initial design and process decisions were made to avoid problems later on: what would be 2D or 3D, which would come first, how would the effects be done, what might be reused? The workbooks pulled as much of this information together as possible. Most importantly, it got the creative supervisors thinking about the sequences as a whole and how to use the crew as a whole to achieve the objective of the sequence. It was kept as a creative meeting, but the information from it was useful to production management for estimating cost and complexity. Of course, during production things would be changed as needed--blueprints have to become buildings after all--but the team had a strong starting point.

Bill Desowitz is senior editor of AWN & VFXWorld.