Sid represents a quantum leap forward for Henson puppeteering. All images ™ & © 2008 The Jim Henson Company.

One day in 1955, Jim Henson glued a pair of cut-in-half ping-pong balls onto the sleeve of a coat his mom had thrown away, slid it over his arm and gave birth to a frog named Kermit.

Animators and puppeteers have at least one thing in common -- they both use their hands to bring their characters to life. A traditional animator once classified (dismissed?) CGI as a form of puppetry. Perhaps he was onto something; perhaps it was inevitable that those two media would someday merge into a new, hybrid form of animation.

At Jim Henson Productions that hybrid is known as HDPS -- the Henson Digital Puppeteering System, and on Labor Day its first full-tilt creation, Sid the Science Kid, joined PBS Kids' lineup of educational shows.

When it comes to complex characters, it's SOP for puppeteers to work in tandem. It takes two people to make Sesame Street's Ernie talk and wave his arms around at the same time: one controlling his head and an arm while the other lends (ahem) a hand working the other arm.

Henson took it several steps further in movies like Labyrinth and the company's Dinosaurs TV series. In those efforts, actors encased in head-to-toe character costumes mimed out a performance while off-camera puppeteers provided not only their voices, but animatronic facial expressions and mouth movements via radio remote control.

In Sid the concept takes a quantum leap forward and into the realm of animation. Start with the mind-meld of two puppeteers acting as one... give the voice/face puppeteer computer-based controls... replace the character costume with a motion capture rig... then have the mocap performers interacting with each other from across a mocap stage, pretending they are side by side in the scene being shot (they can't be next to each other because half of them will be scaled down to child-size).

If it sounds complicated, it is; impossible, however, it's not. Henson's system is pumping out animation in real time -- and in multi-camera perspective, complete with camera moves. It's the literal equivalent of shooting a live, on-stage sitcom that happens to star cartoon characters.

On the mocap stage, PVC piping stands in for the CGI "sets."

Katy Garretson has directed Frasiers, Freddies and George Lopezes. She's a veteran of multi-camera production, but had never worked in animation or on kid shows until Sid. With six episodes of the show's 40 under her belt, Katy's now an old pro at this new technology.

"They told me they wanted to try a live-action person, they wanted a sitcom style. The show is about kids, families, friends and school -- they wanted someone familiar with working with actors. The script they gave me looks like a regular sitcom script, but the difference is when you walk onto the stage. There's no sets, no dressing rooms, no cameras. They were there, but in different forms."

Mocap took place on a 40x60 Hollywood stage, its rubber floor mapped out with PVC piping indicating where the CGI furniture for each "set" is located. Actually, the floor is mapped out twice, the second time at a larger scale -- the "kids" side of the studio. "We had all these different worlds, different realities within this rubber matte. When dad puts his hand on his son's shoulder, they're actually 30 feet apart. There's also a performer who plays a baby, so there was a third reality in the corner we had to shrink down further."

Katy goes on to describe a virtual studio where the prop master sits at a computer and "punches" props into the scene and "camera" operators work at joystick stations. "It's kind of like a video game. Their virtual cameras are like mini techno-cranes. They can do 360-degree moves without getting in each other's way. They can go above or below the set and get any shot you want.

"I was able to flex my camera creative muscles a little more on this show."