Designing the Hot Chocolate sequence was like a giant puzzle with eight waiters, two chefs, the conductor and a hot chocolate cart all packed into the center aisle, with dance movements thrown in for good measure.

The waiters were rigged to handle broad actions, including arms that twist 360 degrees so that they could pour hot chocolate while performing back-flips. Like the background kids, their faces were only rigged for minimal control. The idea is that they are absorbed in their Bubsy Berkeley moment, and “Hot Chocolate” is their only mantra. Special rigs were provided to animation from the effects department to control the arcs of the squirting chocolate, which needed to be tightly choreographed to the camera as well. Cups, saucers and trays were flying throughout the scene, tossed by a character in one split, but caught by a character in another split.

Tight coordination between integration and animation was necessary to make all of the elements work together. Up to this point we had always moved shots forward out of MotionBuilder (integration) and into Maya, but John Matthews was now anxious for a tool that would allow us to go the other way as well. This is because some animation tasks are easier to execute in MotionBuilder because of its unique tools and ability to handle more than three characters at a time. Character setup supervisor JJ Blumenkranz and his crew developed a “motion-collapse” script that enabled us to bake all of our composite animation curves back onto the integration rig and bring it back into MotionBuilder as a fresh new file. The animation curves could now be manipulated in whichever package was best suited for the task at hand.

Conclusion
These were the sequences that defined our processes. As time went on the data became more solid out of integration, and shots started moving through the pipe much faster. Over time the pose-libraries were filled with more reliable expressions for each character and the facial performances, including dialogue gradually improved as a result. Many of the pose-libraries were transferable to other characters as well — especially the adult Tom characters (Conductor, Hobo and Santa). Even so, it seems that every new shot carried with it some whacky problem that had not been anticipated. The difference is that now those problems did not seem insurmountable. For the most part, we knew where we were going and it was more of the same routine to the finish line. The costs were being monitored very carefully, so we had to stay focused on efficiency and choose our creative battles wisely.

I would like to reiterate that it was neither the design nor the intention of this production to create “photoreal” humans as it is often suggested. It is a stylized film with a painterly quality on every level — including the human characters, which were not designed for micro-expression levels of detail that would be required for photorealism.

However, the level of detail is high enough that critics tend to evaluate the imagery and characters on that level. They are quick to point out the flaws, but dismiss the areas that are in fact working very well.

I believe that there are many moments that are near perfect (within the design scheme of the film). Given the production schedule and shear volume of work, we had to focus on the high-value shots that we believed would make the most significant difference in the context of the film. Because we were producing every pixel of every frame, we had to be smart about which areas would get the most attention — because 16 months goes by awfully fast!

The final installment will focus on the keyframe-animated elements, and will be published upon the release of The Polar Express DVD.

Animation director David Schaub joined Sony Pictures Imageworks in 1995. On The Polar Express, he worked with director Robert Zemeckis and noted senior visual effects supervisors Ken Ralston and Jerome Chen. He was previously a supervising animator on Stuart Little 2, for which he and his team received a VES Award (Visual Effects Society) for “Best Character Animation in an Animated Motion Picture.” His other film credits at Imageworks include the Academy Award nominated Stuart Little, Cast Away, Evolution, Patch Adams, the Academy Award nominated Hollow Man, Godzilla and The Craft.