For the first time ever, Homer and Bart Simpson are brought to the screen as three-dimensional characters, rendered in state-of-the-art computer animation by Pacific Data Images. "Treehouse of Horror VI," the 1995 installment of The Simpsons' popular Halloween specials, features Homer3, a parody of a memorable episode of "The Twilight Zone" in which a young girl passes through a wall and is trapped in the 4th dimension.

In the climactic moments of "Treehouse of Horror VI," Homer accidentally steps into the third dimension while desperately trying to avoid his sisters-in-law, Patty and Selma. Having lived his entire life in the 2D world, Homer enjoys his new depth until, through a minor mishap, he creates a black hole which threatens to engulf the entire universe. Bart alone is brave enough to cross over into this other world, in an attempt to save his father.

According to The Simpsons' executive producers, Bill Oakley & Josh Weinstein, "PDI has provided a caliber and quality of animation never before seen on series television ... with a surprise ending so stunning that most of America will still be in shock on Monday morning."

Computer-generated backgrounds are filled with quirky mathematical equations and historic CG references. Homer finds himself on a bright green infinite grid plane, and runs past a replica of the temple from the CD-ROM sensation, Myst.

In the early stages of production, maquettes of Homer and Bart were used as reference, digitized into the computer and refined to create convincing 3D versions of the characters. PDI animators quickly found that a whole new set of movements were needed to capture the spirit of Homer and Bart in 3D. This included the development of several small hand gestures and nervous ticks that convey Homer's signature nervousness and Bart's mischievous nature -- even when the virtual camera and characters are standing still.

"PDI did a terrific job. They made Homer so real it kind of scared us," said Richard Raynis, producer for The Simpsons.

More than 3 1/2 minutes of computer generated character animation were created by PDI for The Simpsons' "Treehouse of Horror VI," representing the first time a traditional 2D character has been re-created in 3D form for television.

PDI animators also provided a seamless transition effect from cel to CG animation as Homer and Bart pass through the "mystery wall." PDI worked closely with the creators of The Simpsons to transform Homer and Bart from 2D cel animated characters into 3D form.

According to PDI Animation Director Tim Johnson, "Homer and Bart are icons of popular culture, but we're used to seeing them as flat 2D characters. In 2D, when Homer is just standing there not moving, it's OK. But get him into the 3D world and its another story altogether."

Other challenges faced by PDI included creating facial gestures, and synchronizing lip movements to the hilarious Simpsons voice track. Once the motion was complete, background elements and special effects such as the highlights and glints that spring from a sparkling road sign were added by PDI effects animators. PDI lighting specialists added beauty lighting for the characters and dressed the scenes for final rendering.

For more information, check out our How Did They Do That? web page dedicated to Homer3.

Matt Groening. The Simpsons TM/Copyright © and Twentieth Century Fox Film Corporation. All Rights Reserved. TM/Copyright © Pacific Data Images.