It's one thing to tell Mr. Incredible, Elastigirl, and the gourmand rodent in Ratatouille what to do.

It's another to get Tom Cruise to hit his marks, and Jeremy Renner to run exactly this way, and Paula Patton to whoosh into a room on just the right beat.

Making the transition from computer-animated movies - Oscar-winning computer-animated movies, by the way - to working with real actors, on real sets, in real time, was not the easiest thing Brad Bird has done.

"It was definitely an adjustment," acknowledges Bird, who makes his live-action directorial debut with a "modest little" $140 million Paramount franchise called Mission: Impossible - Ghost Protocol.

"I had to learn fast. It was complicated and the schedule was tight and the canvas was broad. . . .

"But I think it would have been a bigger adjustment if I had gone from hand-drawn films to live-action," he adds. "In CG films, you still work spatially, and even though your tools are different, you're still lighting a scene a certain way - you can place lights virtually. And you can . . . even select lenses that mimic what a real lens does."

That said, Bird - who did hand-drawn, beautifully, with 1999's The Iron Giant before moving on to Pixar's The Incredibles and Ratatouille - still had a lot to learn.

"When I first started on Mission, I wanted to cut right when the shot ended in my mind," Bird explains. "I wanted it to be like animation, where I only need it from here to here. And then I'm going to cut to this angle, and then I only need this moment. . . .

"But I'd be there, and Tom was going, 'You might want to let this moment play a little.'

"And I was like, 'Oh, OK, I get it!' All this equipment and stuff is expensive, but film is relatively cheap. So I got a little more loose about letting moments play, and, if actors were on a roll, keeping the camera going.

"Animation is all about planning, so that you don't waste a frame, because it's time-consuming and expensive to do each frame.

"But with live-action, most of the expense is in getting there. When you're there, you can roll a bit and play in the sandbox."

The sandbox in Ghost Protocol, the fourth film in the Mission: Impossible series starring Cruise as IMF agent Ethan Hunt, was pretty big: "We shot in five countries," Bird reports. And he shot inside, on, and around Burj Khalifa, the towering glass spire in the United Arab Emirates that happens to be the world's tallest edifice.

An elaborate, and vertiginous, sequence in which Hunt and his team must hack into the Burj Khalifa security system was shot using IMAX cameras - as was a huge sandstorm chase scene through the streets of Dubai. Mission: Impossible - Ghost Protocol plays exclusively in IMAX theaters starting Friday, and then opens wider Dec. 21.

Despite his impressive animation credentials (The Incredibles won the best animated feature Academy Award in 2005, Ratatouille won in 2008), Bird has been wanting to make a live-action film for years now.

"People are surprised when I tell them," he says. "It's just never happened before, due to a variety of reasons."

Like those Oscars, and the millions in box-office receipts?

"Well, when you make one successful film, your opportunities to make something similar are huge," he says. "And if you like to do one kind of film, and you make one that works, you'll have many times at bat with that kind of film.

"But I've always liked jumping around. . . . My favorite directors are people like Francis Ford Coppola, who will do Godfather one minute and then One From the Heart, Apocalypse Now, and then Dracula, you know what I mean? You're all over the place.

"I think my animated films are different from each other, but once I made one, the opportunities did arise to make another. And I just finally said, 'Look, I want to make a variety of films, and I need to make a live-action film, too.' You just want to always be expanding your tool kit."

It was J.J. Abrams, who directed 2006's Mission: Impossible III and was hired to produce its sequel, who thought Bird would be the right man for the job.

"I've known J.J. for a while, and we had talked over the years about doing something together, but the timing never seemed to work out."

Another project of Bird's - 1906, about the devastating earthquake that hit San Francisco, and the fires that ensued - was stuck in limbo. And Bird had made a visit to Abrams' office in L.A.

"I dropped by Bad Robot," he recalls, "and J.J. asked me what I was doing, and I said I was looking around for something. And I got an e-mail at 11:30 that night that just said, 'Mission?' I didn't even know that they were doing a new one!"

Bird said a big appeal of the series - in addition to "the popcorn goodness of its central premise" - is that Cruise had stated from the get-go that he wanted each installment to reflect the individual style, and aesthetics, of its director. Brian De Palma did the first, John Woo the second, Abrams the third, and now Bird.

So what does he think he has brought to the table?

"I would say the tone that I was looking for in this was closer to something like Raiders of the Lost Ark, where you have a lot of jeopardy and suspense and action, but you're also throwing humor in there. I think that there is humor to be found in tension and that if you do it right and don't undermine the action/adventure part by being too silly - if you take it out of the characters and the situation - it can be really fun.

"So, I would say it's a little more aware of its own movieness and goofiness. But not - I hope - at the expense of any of the tension."

Contact movie critic Steven Rea at 215-854-5629 or srea@phillynews.com. Read his blog, "On Movies Online," at http://www.philly.com/philly/blogs/onmovies/