Hollywood directors experimenting with groundbreaking special and visual effects found themselves apologizing to comic-book fans for slipped release dates and showing raw footage at the 2006 Comic-Con International, the nation's largest comic book convention.

More than 100,000 comic-book fans jammed into the San Diego Convention Center from Thursday through Sunday. Studios discovered an appearance at the show is best served by unveiling new or exclusive movie footage in exchange for instantaneous feedback from zealous fans.

Directors also apologized for slipped movie release dates, pointing to difficult visual effects for the delay. "We had to come up with a whole new program to create the fire, and to be honest with you, that's the reason it's been taking so long to finish the film," Mark Steven Johnson, the director of "Ghost Riders," told the crowd on Saturday. "A lot of the Sony Pictures Imageworks effects were groundbreaking. Sony Pictures unveiled at Comic-Con first-time footage of "Ghost Rider," an adaptation of Marvel Comics hero Johnny Blaze who sells his soul to the devil to save his father. The event brought out Johnson, along with producers Michael De Luca and Avi Arad and stars Nicolas Cage and Eva Mendes. More than 6,500 fans packed into Hall H, the convention center's biggest room, to see the fiery visual effects.

Johnson said Cage, who plays lead character Johnny Blaze, wore a green neoprene hood over his head with interactive lights to mark the spots that fire should appear. "We'd get his expressions and movement, then digitally remove his head and put the flaming skull in its place," he explained.

The audience also roared for Sony Pictures' "Spider-Man 3." Director Sam Raimi apologized to the crowd for having to run raw footage of cast members Tobey Maguire, Topher Grace, Thomas Hayden Church, Bryce Dallas Howard and Kirsten Dunst because visual effects on the movie proved complicated and time consuming. Comic book fans in crowded Hall H didn't seem to mind.

"You're going to see really raw stuff, as some shots we slugged together this week," Raimi explained. Bill Mead, an entertainment industry consultant and DCinemaToday.com publisher, said it's quite common for schedules to slip as more visual effects make their way into movies. Technology that allows studios to ditch celluloid and deliver movies to theaters digitally has opened the doors to more computer-generated visual and special effects. Mead said Hollywood has been restrained by 35 millimeter film and now many production houses are leapfrogging into digital. Not just digital, Mead said, but 3D, such as the newly released Columbia Pictures' "Monster House." Directors from James Cameron to Steven Spielberg are putting new energy into 3D effects as more studios and theaters demonstrate the capabilities possible with digital projection technology.

Dan Gregoir, CEO and founder of pre-visualization house Halon Entertainment, agrees. "We are getting busier and busier, primarily because a higher percents of movies are using visual effects in some way, either in a visual-effects extravaganza or it's needed to accomplish the plotline or storyline," Gregoir said. "Sometimes the visual effects are invisible and not always used the way you might think."

Some of Halon's 21 artists worked with directors to flush-out ideas, shots, sequences and concepts before shooting began on "Ghost Rider" and "Spider-Man 3."

View clips of the Comic-Con Sony Pictures here.

Video on visual effects in Ghost Rider