A thin line separates Jennifer Garner's (search"Alias" character from reality.

It's a series of thin lines, actually -- sketches that take her sexy superspy from the world of live action to the world of animation.

The seven-minute "Animated Alias" (searchon the new third-season DVD of the ABC thriller is the latest example of a renaissance in the short-cartoon format inspired by the success of 2003's "The Animatrix." (search

The movies "Van Helsing," "The Chronicles of Riddick," and the TV series "Buffy the Vampire Slayer" also have tried to expand their reach through animation -- from short stand-alone films to TV shows.

Short cartoons, like music soundtracks in the 1980s, are becoming popular movie and TV spin-offs that have an artistic legitimacy beyond simple merchandising.

And with 3-D computer animation such as "Shrek 2" and "Finding Nemo" (searchtaking over the feature film market, these shorts may be among the few places fans can see traditional hand-drawn animation.

"There are certain sign posts that you've broken through into the subculture," said "Alias" creator J.J. Abrams. "The idea of having the show animated, to me, was like crossing that threshold."

Although the cartoon is very brief, Abrams described it as a chance to dip his toe into ink and paint.

"It was done as the beginning of a larger story that we would love to continue doing as an animated series, whether something for DVD or for television," he said. "One of the things I would love to explore, down the line in animation, is the ability to do things that are physically prohibitive and essentially impossible on a weekly series budget and schedule."

The live-action cartoon trend started with "The Animatrix," (searcha series of animated shorts that ranged from realistic computer graphics to moody Japanese anime -- telling side stories from "The Matrix" and adding to the plot of the "Matrix" sequels by detailing supporting characters and providing background history of how the Earth became dominated by machines.

"With animation, it costs just the same if you portray something mundane and ordinary, like a guy running down the street, or if you show a battle between robots and people," said Peter Chung, who directed the segment "Matriculated" and made the animated shorts "Aeon Flux" for MTV in the 1990s. "It becomes less expensive (comparatively) the more fantastical the imagery is."

Most recently, Chung directed "Dark Fury," a 40-minute cartoon that connects the Vin Diesel sci-fi action flick "The Chronicles of Riddick" with its predecessor "Pitch Black."

The DVD of "Dark Fury" shows how his galactic killer made his way from being stranded on a planet full of nocturnal monsters in the first movie to his epic battle with intergalactic fascists in the second film.

Similarly, "The London Assignment" cartoon serves as a prequel to "Van Helsing." The battle in the live-action movie between Hugh Jackman and the murderous Mr. Hyde atop Notre Dame cathedral in Paris is previewed in the cartoon when the two foes face off for the first time in England.

Apart from promoting the live-action movies, both those cartoons provide die-hard fans with more story. Similarly, "Star Wars" (searchcreator George Lucas authorized a series of animated shorts on the Cartoon Network that chronicled the "Clone Wars" from his sci-fi prequels.

The wars began at the end of "Star Wars: Episode II -- Attack of the Clones," but the entire conflict wouldn't fit into his next and final chapter, "Episode III -- Revenge of the Sith." The 20 short "Clone Wars" cartoons connect the dots between the movies.

For some TV shows, meanwhile, animation is a chance at eternal life.

Fans of "Buffy the Vampire Slayer" have been salivating for more stories since the show went off the air last year after seven seasons. But star Sarah Michelle Gellar (searchhas expressed little interest in reprising her role.

Replacing her with another actress might be too jolting, but replacing her with a cartoon may be more palatable -- even if a substitute performs the voice.

Animation artist Eric Wight has created concept drawings for the proposed animated "Buffy" series, which is being shopped around to networks but could also turn into a DVD film.

The stories would all take place during the characters' first year together in high school -- which was the first season of the series. "Going back to the high school environment, they can spend as much time as they want there," Wight said.

"Buffy" creator Joss Whedon wants "to tell all the stories that he couldn't tell in the beginning, bigger stories with bigger monsters," Wight added. "He didn't want any monsters that looked like guys in suits. Here was his chance to do a dragon or do all different kinds of monsters."

The rest of the cast was willing to provide their own character voices and allow their likenesses to be transposed into cartoons. Gellar is the exception, "which is why her design always stayed in that generic cute, blond girl mold, but never came back to her exactly," Wight said.

Sometimes animation is not so free of its star, however. Wight helped develop an "Austin Powers" cartoon that fell apart when Mike Myers backed out.

And someetimes the character can be inspiration enough.

Brandon Schultz, president of ImajiMation Studios, liked Wesley Snipes' vampire hunter so much that he agreed to a severely abbreviated production schedule to make a three-minute cartoon for the upcoming feature "Blade: Trinity." It will be released as a DVD in the soundtrack album Nov. 23. (The movie comes out Dec. 10.)

"The take is just Blade and (rapper) RZA kicking butt on a bunch of vampires. ... It's a real good excuse to have a lot of fun," he said. "We got vampires with gold fangs!"