LOS ANGELES » It’s official: The hammer of Thor and the shield of Captain America will fly straight at moviegoers in 3-D, which is really no surprise considering the current stereoscopic craze on the studio lots of Hollywood. What is unusual is the eagerness of each film’s director to take his case for 3-D directly to the fans at Comic-Con International.

Next Saturday, Marvel Studios has the final studio presentation in the expo’s biggest room, Hall H, and "Thor" director Kenneth Branagh will use that climactic slot not just to introduce some of his cast — a cast that includes Chris Hemsworth, Natalie Portman and Anthony Hopkins, although it’s unlikely that all three will be in San Diego — but also to persuade skeptical fans that 3-D will add new dimensions to the 2011 blockbuster, and not just in the obvious way.

"We came to feel that in our case 3-D could be the very good friend of story and character for a different kind of experience," Branagh said, taking a break from post-production. The filmmaker said the terminology of the 3-D process initially made him cringe — at first, it was "math and physics and way over my head," he said with a chuckle — but then he started to pulse with the unexpected artistic opportunities.

"It’s another draft of the story that can reveal itself in a different way," he said. "I had a healthy degree of skepticism up front. … I’ve become somebody extremely excited about working with possibilities of doing it this way."

"Thor" is a version of the old Norse myth that’s been heavily processed by the cosmic dream factory known as the Marvel Comics universe. The film’s title character spends part of the film in Asgard, a celestial kingdom, and part in a Hopper-esque town in New Mexico, where Thor (Hemsworth) is exiled by his father and monarch, Odin (Hopkins). The film is due May 6.

Branagh said he changed his approach with some scenes to maximize the 3-D benefits. "A pretty careful conversation is what we’ve been having for quite some time about what we know has to be the most sensible decision: Is it led by story? Can this offer a different type of experience and exploit what we have in the story? It absolutely can. … We travel very long distances in the movie, and the opportunity to export and exploit the journey of the hero is really offered up as a great potential enhancement here."

"Thor" will be the first Marvel film in 3-D. The second will be "Captain America: The First Avenger," due July 22, 2011. The director of that film, Joe Johnston, has experience with stories of the fantastic (his credits include "Jurassic Park 3" and "The Wolfman"), but he said he was also skeptical of 3-D after seeing some recent films make missteps.

"I think it tends to be overused and can be a little bit gimmicky," said Johnston, who began shooting last week in London but will travel to San Diego for Marvel’s Comic-Con panel. "A lot of people are using 3-D now because they feel have they have to. … That will come and go, and the pictures that deserve to be in 3-D will continue to be. When it’s done bad, it can make you carsick."

Johnston did a one-day test shooting with a 3-D rig — as opposed to shooting in 3-D and converting — and said it was "a nightmare" due to bulky gear, calibration issues and restricted filmmaking options. He said he’s a firm believer, though, in the conversion approach if done right, and he’s enthused to move forward. "It’s a new challenge and it’s exciting," Johnston said.

Both "Captain America" and "Thor" use 2-D for principal photography, but the considerable special effects for the films were conceived and executed from the beginning in 3-D, something that will help them avoid certain pitfalls, said Marvel Studios President Kevin Feige.

Feige and Branagh were interviewed together in a conference call with the Los Angeles Times. They acknowledged a negative stigma to 3-D, at least in the eyes of savvy fans like those who attend Comic-Con.

"I’d say there’s not a great feeling out there for conversion based on some of the films that may have succeeded financially but had their artistry come under fire," Feige said, not naming names, but most likely referring to "Clash of the Titans," the Warner Bros. release that surpassed $490 million in worldwide box office but was savaged by critics for a rushed 3-D conversion that many saw as especially clumsy, distracting and ill advised.

Feige, in London for "Captain America," pledged that "an unprecedented amount of time" would be devoted to the conversion process. He also said the films will benefit from the fact that the 3-D choice was made early on with passion and planning and not in post-production, as was the case with a flurry of films that came on the heels of "Avatar" and its historic box-office success.

"In being able to think in 3-D from the start — and having every bit of our special effects rendered in true 3-D — we have the opportunity to do it right," Feige said. "When you’re working with a director like Ken Branagh or Joe Johnston, they’re not going to settle for less than perfect image. They’re not going to settle for something that isn’t up to the artistry of everything else they’ve done on the film. … They’re not going to put on some overlay in the last 10 to 12 weeks of post-production for a fiscal reason."

With "Thor," especially, Feige said, the citadels of Asgard and the rainbow bridge at its gates lend themselves to 3-D. "It’s one of those maybe rare times where 3-D accentuates the story and the way the viewer is brought into this new world. That’s what ‘Avatar’ and ‘Alice in Wonderland’ were all about — going into new realms, new worlds. … I think with the ‘Harry Potter’ films and ours, you’re about to see a slew of movies where 3-D was done by people who had the time."