The animated feature “Monster House” has two well-established executive producers in Steven Spielberg and Robert Zemeckis, but its director Gil Kenan is a newcomer who won the job on the basis of his UCLA student film, “The Lark.” And though the cast includes major names like Steve Buscemi, Maggie Gyllenhaal, Jason Lee and Kathleen Turner, the real stars are three youngsters, Mitchel Musso, Sam Lerner and Spencer Locke, as the teens who investigate the scary old house and uncover its deepest secrets. Lerner and Locke accompanied Kenan to Dallas to talk about the movie, made with the performance-capture animation technique previously employed in “The Polar Express.”

The script hadn’t specified that the picture would be animated, but when Kenan came aboard, he was convinced that it was the only way to go. “I think that you need an animated reality for a movie like this to seem playable, to seem like you can actually as an audience give over to the story,” he said. “Animation really creates an environment where a story like this could play out, and so for me there was never any question to it. I came in after reading the script knowing that this was the only way to make the movie.”

But that made for a real challenge. “Performance-capture was a brand-new thing at that point,” Kenan explained. “Zemeckis had only just started shooting ‘Polar’ when I first met with him. And so there was no real kind of template for it, or textbook or anything. And I knew for ‘Monster House’ I would want to create a different kind of movie, a more stylized world, and a looser story. And so I knew that we’d have to re-invent the wheel, in a way.”

In performance-capture animation, real actors are filmed performing the scenes together on an empty soundstage, wearing special suits and shoes and with plastic reflective dots glued to their faces. The captured performances later serve as the basis for the elaborate computer-generated animation. “It’s what makes this process really unique from traditionally animated films, where an actor goes into a sound booth and records a line, and then the actor that they’re having a scene with comes in two weeks later and does the second half of the conversation,” Kenan said. “A lot of amazing animated films have been done this way, but to me there’s so much humanity lost there, there’s so much of that real interaction that happens when you put two people in front of one another and they can look in each other’s eyes and relate to each other and think about what the other person is saying. And it’s not just a vocal thing–it’s a physical thing, too. The body language is so tied to the next line you’re going to say to respond to them. So all of that stuff became the way that we made the film–all of that is really integral to how this film ended up.”

For Kenan’s vision to be realized, though, careful casting was required–especially of the three youngsters. “It was hard, because I knew that I wanted real chemistry,” he said. “The worst thing for me is when there’s a kid performance on screen, and it just rings false–it just feels like things were kind of either beaten into the kid, or overprogrammed, and it feels unnatural. And so first I had to find kids who were smart, and could communicate with me and be real people. The truth of it is, I didn’t just cast them for their individual abilities as actors, although they’re all truly accomplished actors and are able to carry the story on their own shoulders. I really looked for three who, when put together, had the right energy, the right chemistry, because it’s so critical to a story like this, that really depends on the interplay between three kids who are at this really awkward, critical point in their lives. And so I found Sam, I found Mitchel, and I found Spencer, but it wasn’t until I put the three of them–after going through a thousand kids reading, and there were many more who were reviewed through head-shots and tapes and such–together in a room and felt like I believed that these kids could exist in this world, that they could bring life to these characters” that he made a final decision to cast them.

“We must have gone in [to audition] like ten times each,” Lerner recalled. “’Cause it’s a huge movie–Steven Spielberg, Robert Zemeckis–and they’re trying to find these kids. So they searched, like, everywhere. And we were so happy to have been a part of it.” He added that the eight-week shoot began with a rehearsal period that Kenan made as helpful as possible. “Gil built a set of DJ’s house,” he said–the house from which the three youngsters watch the “Monster House” across the road–“so that we could rehearse in it. Which helped so much.”

Kenan explained, “I really believe that for a film like this, which could on the face of it be a very technical shoot, it’s important to feel comfortable in your character. And also I had to create a relationship with my actors, and the rehearsal period really helped that. Once it came time to shoot, it’s not like a traditional live-action film, where an actor comes out in a costume or a wig, and they’re in a set with props so you can at least kind of imagine the world. They’re coming out in wet suits with dots on them and a bunch of dots glued to their face…”

“And chicken-wire props!” Lerner added.

“Right,” Kenan continued. “It’s pretty surreal, and so if you don’t create a rapport, if you don’t create at least a comfort zone of character and story, you could end up with something pretty frightening. And so my job was to create a cocoon around them, and try to erase all the technology, because that’s not their job. Their job is to be characters.”

“It was weird,” Locke interjected. “We had to imagine everything. You know, okay, a house is chasing you down the street, when really we’re just in a soundstage.”

But Kenan praised the way the actors responded to the challenge of the format. “It’s an interesting thing that I watched happen on that stage,” he said. “I saw that on the first day, you come out and it’s a bit of a shock because you’ve lost your safety net. An actor a lot of times gets a lot of inspiration from putting on the costume or putting the shoes on for the first time. But what happens is that as soon as the acting instinct kind of kicks in, which happens about a day into it, you begin to trust your character, and at that point you become a pure character and much more go back to kind of theatre boot camp and the acting classes that I did when I was a kid–where you don’t have sets, you don’t have costumes, you just have yourself and your own acting ability. I think everyone was able to channel that and let it carry them through the rest of the shoot.”

After the cast had completed their work, Kenan put two more years into completing the picture. “All I shot when they were on stage was performance,” he said. “All the camerawork had to be done virtually after they all went home. For me the real task was–because I think a lot of animators forget the fact that there are some rules of narrative filmmaking–I just really wanted this to have a sense of real filmmaking, that it wasn’t just cameras zipping around and doing backflips. And the animation…was a huge undertaking. There were hundreds of animators whom it took to translate their performances to characters on screen.”

Lerner and Locke were enthusiastic about the finished film they’d shot so long ago. “It was amazing to finally see it,” Lerner said. “A real movie!” Locke agreed.