LOS ANGELES — To an outside observer, there is no rhyme or reason for the way Billy Crudup selects acting roles.

There are times when he seems to be the darling of the independent film world with movies like "Pretty Bird," "Dedication" and "Jesus' Son."

Then he will pop up in a Woody Allen movie, "Everyone Says I Love You," or a popcorn action film like "Mission: Impossible III."

His new role, as the brooding, humanity-disconnected Dr. Manhattan in "Watchmen," lands him in the middle of a fan and media frenzy like no other movie he has made.

Crudup explains, during an interview at the Beverly Hilton Hotel, there actually is a method to his script selection process.

"When I am reading a script, and I unconsciously put it down after 20 pages, and start thinking about the character, that is when I know it is something to latch on to," Crudup says.

He felt that way almost immediately when he started to read the script for "Watchmen." He tried to figure out what was going on with the characters. He found the story to be "quite subversive" in terms of what he had expected it to be when he heard it was going to be a comic book movie.

It is not surprising Crudup had such a quick reaction. He was given the challenging task of playing the only superhero in the film who has super powers. An accident changed Dr. Manhattan into a being who can manipulate matter and can see the past, present and future all at the same time. The character also is dealing with the erosion of his own humanity.

"My first thought was 'How do you do that?' I don't understand. I really didn't understand. That's one thing I gravitate toward in characters. Things I don't understand," Crudup says. "That's not to say I don't understand the practicalities of it. I don't understand the psychology of it. I don't understand what motivates him.

"I don't understand how to render that in a real way, in a way that is compelling."

Director Zack Snyder apparently believed Crudup could handle the demands of the role. He certainly didn't cast Crudup because he physically fits the demands of the role: a 6-foot-4, blue-skinned being who glows.

Crudup stands 5-feet-8. The New York native is dressed in a gray, long-sleeved T-shirt and jeans. He looks more like a guy who would deliver a pizza than play an all-powerful superhero.

All Crudup had to do was find the emotional tone to play the role. Computer effects supplied the rest.

During the long filming process, Crudup's face was covered with 140 black devices smaller than a dime that recorded the muscle movements in his face.

He was filmed and then a computer removed Crudup's image and replaced it with the digital creation.

"For better or worse, it is definitely my performance. They are so accomplished with the level of detail and nuances that they can manufacture in the computer," Crudup says.

He smiles and adds, "I think they didn't need more than seven or eight dots. They had 140 standing by in case I did something."