Robert Zemeckis may just be the father of the performance-capture, 3-D mania sweeping through Hollywood.

His "Polar Express" inspired DreamWorks animation chief Jeffrey Katzenberg to declare, "It was the most exciting experience I'd had in a movie theater."

Before adapting the beloved children's book in 2004, Zemeckis had such diverse films to his credit as "Who Framed Roger Rabbit" and the Tom Hanks tours de force, "Forrest Gump" and "Cast Away."

Then came "The Polar Express," which incorporated Hanks into multiple roles, the animated epic "Beowulf" and now "A Christmas Carol," in theaters.

Through the magic of performance-capture, Jim Carrey is rendered as eight characters, including perhaps the most portrayed and parodied Dickens character of all, Ebenezer Scrooge.

Zemeckis told a Comic-Con International audience in San Diego that not everything works in this format that he has worked so feverishly to perfect. For instance, in confirming that a sequel to "Roger Rabbit" was afoot, he said that the cartoon characters would continue along a 2-D path (although the humans might meet a computer-generated fate).

"A Christmas Carol," though, was a perfect fit, he said.

"If you read the actual novel, it's really very trippy. It's really surreal, and it's really cool, and it's very cinematic. I actually thought that we finally now have the filmmaking tools to realize what Dickens actually wrote, so I thought a re-visioning of it would be really fun to do."

Zemeckis was the first featured speaker at a Disney 3-D panel at the July convention, where he discussed the process with comedian and moderator Patton Oswalt (the voice of Remy in "Ratatouille").

Oswalt kept the discussion fanboy-friendly, pointing out that Carrey is now tied with Alec Guinness ("Kind Hearts and Coronets") for most roles by a single actor in a film.

Here's some of Oswalt's back-and-forth with Zemeckis:

Oswalt, pointing to a screen where the characters Carrey plays are displayed: "That is amaz ... that's Jim Carrey as a little kid. Oh my God! That's just freaky. So let's just get your reaction to the phrase 'dead eyes and the uncanny valley.' Let's get that over with right now."

R.Z.: "'The uncanny valley' is a term that was coined for robots, for mechanical people, for animatronic dolls. I don't think it was ever intended to be used for cinema. I see a lot of uncanny valley in your everyday movie. I see it when you have a kind of a mediocre actor ..."

P.O.: "Hey!" (Audience laughter)