All images © 2006 Columbia Pictures Industries, Inc. and GH One Llc. All rights reserved.

Eighteen months after pioneering a groundbreaking motion-capture technology with The Polar Express, Sony Pictures Imageworks is back at the forefront of the animation scene with an innovative computer-generated feature film. In Monster House (released by Sony Pictures on July 21), the “star” is a decrepit house that seems to be alive. An animated horror movie? That will be quite a departure from the traditional talking animals and other light comedies that we have come to expect from Hollywood’s dream factory.

From the beginning, director Gil Kenan opted for a very stylized look. Although it would employ the same ImageMotion technology as The Polar Express, Monster House didn’t use it to try to recreate reality in the computer. Visual effects supervisor Jay Redd confirms, “Our characters in Monster House are indeed human, but we always approached them as stylized — almost as if they were puppets. If you look at their proportions, you will notice that the heads, eyes, hands, and feet are larger than they should be. Also, we didn’t concern ourselves with moisture, eyelashes or even real hair. We started our character modeling by creating actual clay sculptures of each character. Once a sculpture was approved, it was laser-scanned in, and final clean-up and patching, costumes, etc. were created. The most interesting aspect here is that we avoided symmetry at all costs. So many people model one side of a character and then simply mirror and flip to get the other side, which is highly unnatural. Admittedly, modeling and rigging non-symmetrical characters is a lot more work for the crew, but the results are so much more interesting and subliminal.”

The all-important House was designed like a real house, with sketches and blueprints. “The modeling and rigging team created a fantastic rig,” says co-animation supervisor T. Dan Hofstedt. “It had to have that flexibility to appear normal in its at-rest default pose, but it also had to be able to expand and rip and shred into this horrific beast. Actually, there were about 20 different rigs within the House rig, with a total of around 40,000 animatable controls for everything that moved on the house.”

 

Adds Redd, “We had to build an incredibly robust character because the story demanded it. We mapped out where every board would break, how they would break, etc. Character rigging supervisor JJ Blumenkranz and his crew had to get all the right pieces moving in the just the right way. The texturing part of the house is also incredibly complex. Audiences may not notice right away, but the house ‘breaks down’ over the course of the film. There are many, many layers of paint on the house, and this all had to be created in textures and shaders. It is one of the most complex characters I have ever been involved in creating!”

Testing Motion Capture vs. Keyframe
In order to decide what the best approach to animation was, the crew did three versions of a test shot for each of the main human characters. The first version was mocap facial data only. The second version was keyframed accents added to the mocap, and the third was keyframed only with no mocap, using the video reference of the performance as a guide. “We found that the best results were obtained with the second method,” Hofstedt recounts. “So, we usually employed the mocap facial data as the basis for the animation, and then added selective accents and exaggerations that maintained the spirit and integrity of the actor’s performance. Sometimes, the mocap was left alone or only altered slightly, and sometimes for various reasons, the faces were totally keyframed. But by far, the majority of the shots blended both influences.”