The Polar Express animation supervisor David Schaub.

This is the third of four installments in VFXWorld’s The Polar Express production diary. Read Part 1 and Part 2.

To recap, “MoCap/Anim” is the work that the animation department does on top of (or in addition to) the performance capture delivered to us from integration. A description of the animation rigs and workflow is covered in the Animation Rigs & Controls discussion in Part 2 of this series. The shots are delivered to us from integration as Maya files with all of the assets embedded. That includes audio tracks and all the pertinent video references set up on image planes.

Using the performance capture as our foundation, the animation task is to fill in the blanks — but only to the extent indicated in the video references provided to us from production editorial. Often a shot will come with notes from Bob Zemeckis indicating a desired performance change. For example, a character should look left instead of right — or perhaps do a double-take at a specific moment. Other than that, the actor’s performances were sacred unless Bob indicated otherwise. The hardest thing to do in the beginning was avoid the temptation of “helping” a performance along by pushing an extreme or making an action broader, etc. Bob knew these performances inside and out, and his goal was to replicate those performances without any further interpretation by the animators. One exception to this rule is body dynamics that often had to be animated (or re-animated) if there was some external force acting on a character that was not captured on set. The simplest example of this would be upper body animation to support the illusion of a rocking train, especially when the characters are on the roof.

Hero Boy’s movements were performed by Tom Hanks, but the digital artists found that when retargeted to the proportions of a child, the actions look like a slow-motion run on the moon. All Polar Express images © 2004 by Warner Bros. Ent. In

The Sequences
The obstacles we encountered in the first six sequences were among the most difficult challenges we faced on the show. This is where our processes were being established, and where most of what was broken got fixed. I am not suggesting that life was easy after that, but those six sequences taught us much about what we were up against and allowed us to establish a viable workflow based upon the lessons learned. What I will do now is walk you through some of those milestones and lessons that paved the way for the remainder of the film. The dates obviously overlap because there are multiples of shots in play at all times.

Boy Awakes Sequence (BA)
Number of Shots: 18
June-November 2003

June 11, 2003
Our first shot through the pipe is also the first shot in the film where the camera travels in through the window, moves over the bed and closes in on an extreme close-up of our hero (Chris). The reference video shows Tom Hanks lying very still, “breathing slowly and silently.” There is no detectable movement in the close-up video reference, other than a hint of movement in his chest as he breathes. However, the performance capture provided us with some lovely body tremors and twitches. Given the fact that the character is sleeping, it made no sense to use this noisy data — so we turned it off and animated by hand.

When Tom opened his eyes in this shot, his eyes were absolutely fixated as he stared at the ceiling. Although it could not be seen in the reference, lead animator Kenn McDonald added a hint of saccade (tiny intermittent eye movements) to keep the eyes alive. One of those movements was perceivable change in eye direction. When Bob saw this he instantly pointed out that Tom did not do that in the reference video. He was right. Tom’s eyes were frozen in silence as he listened intently for the sound of the bell. A change in eye direction would indicate a change of thought (a distraction), and that was not the intent of the moment. We had missed the point! This is an example of “reinterpreting” a performance, which is something we needed to avoid — a lesson driven home right out of the gate. So we eliminated the obvious directional change, but kept a small amount of saccade in keeping with the natural physiology of the eyes.