Seeing director Gus Van Sant for the first time, in all his extremely shy glory, makes you wonder how he ever ended up in a business as public as film. But Van Sant is a master of disguise. Early on in our interview he reveals how employing Columbo's practice of acting the opposite of how he feels has served him well over the years.

Despite his best efforts, however, Van Sant's nervous nature is palpable. The director of 'Good Will Hunting' and 'Last Days' daintily sips tea from a little white china cup, his hand betraying an almost imperceptible shake. This is coupled with Van Sant's incongruently youthful attire (he is 55 and wears a hoodie and colorful Nikes) and an easy smile that pleats his face like an envelope, all of which makes him utterly disarming.

Van Sant is at the Toronto Film Festival promoting his new movie, 'Paranoid Park.' Based on a novel by Blake Nelson, the film is about a teen skateboarder who accidentally kills a security guard. Like 'Elephant', it is a study in ambience, in this case an ambience borne of the kinetic energy inherent in skating life.

Van Sant talked to us about his anxiety over accurately representing skate culture, the difference between Torontonians and Americans, and a new kind of soundtrack he uses made up of everyday sounds.

Everyone's talking about your use of MySpace to cast the film - can you tell me more about it?

It's not really how we did it. We put a posting, which I guess is a profile - I've been learning from the interviews - it was mentioned in the French press and it's such a buzz word that everyone wants to know how that works. I think it was our Portland casting person who created a profile as a way to get word out that we were having these group casting calls. But the main cast didn't come from MySpace.

In 'Paranoid Park' your cast was untrained, and there's a realism that permeates all of your films. How else do you attain naturalism in your films?

Usually, I'm very happy with the first reading, which is almost like a throw-away. If there's a problem, I pretend it doesn't matter, in a Columbo kind of way. He was a [fictional] detective and he wanted to get information out of people so he'd pretend he was on the wrong track. People would think he was such an idiot that they'd tell him what he wanted to hear - that was his method of getting what he wanted.

I don't do a tricky Columbo thing, I just do a thing where I pretend it doesn't matter if you talk [normally] while the camera's running; I try to make it so the camera's not

Alex (Gabe Nevins) looks pensive in a still from 'Paranoid Park.' (IFC)

the centre of attention. On my sets, I look at the camera like it's this God; it aims in a certain direction and you're afraid to get in front of it. I think I'm pretty camera shy so I know what could be going on in [the cast members'] heads. The Columbo part is me pretending the camera isn't like that.

Does the fact that you're from Portland make this film [which is set in the city] more intimate to you?

The more I stay in the city, the more I emulate it in the films. 'Elephant' is the one that captures [the city] best. [Portland] is pretty laid back - it's sort of like here [Toronto]. There's just this absence of aggression here that we don't have in America - you have this very benign appearance. I'm seeing it mostly when I walk by good-looking guys - [in America] they might give you a look like, 'What are you looking at?' - they don't care here.

How did you decide how to portray skateboarding without being a skateboarder yourself?

I was just talking to a photographer, Ryan McGinley, who has skateboarded all his life. He's a very good New York photographer who's young and knows the New York street culture and skate culture as well as anyone. I was telling him about the movie and I said, 'I don't know how much it really represents skate culture.' I don't feel I'm so divorced from skate culture, it's just capturing it is some other thing - it's almost like representing a pirate ship. Ryan said it's mostly about being outsiders, it's like being gay. That's when I thought, 'Oh, well, maybe it does represent skate culture and I don't even know it.'

Why did you choose Christopher Doyle as your cinematographer? The man who did 'In the Mood for Love' isn't the first person who comes to mind when you think of a movie about skating.

Well, 'Fallen Angels' is completely done in wide-angle lens and that was one of the things I was thinking about; all the skate films are done with really wide-angle lenses. [Doyle] had done it in a dramatic sense.

But there were certain things Chris did that I thought, "I'm not going to use that." When Alex (Nevins) walks down the hall and it gets very slow and dark, I just thought, "Let him do it, but it's not going to work. It's just going to get too dark." And now I think that's probably my favourite shot.

The sound is very peculiar in the film, it's mostly ambient background noise with little traditional music. Did you let sound designer Leslie Schatz have free reign over the film?

[Schatz] was the one back in 'Elephant' who insisted on recording stereo sound. We were doing such long takes that it opened up the ability because we weren't cutting from one scene to another. Usually you're just trying to get the voice and you don't want the noise from the construction outside, [for example] - on a regular film they actually tell you to stop making noises during the take.

In the end it made this big spatial thing happen to the sound so that even when somebody just talks you're hearing the voice come off the walls in true stereo fashion. Ever since then I've realized how important stereo is and how it makes the film so unlike other films.

What people are also really getting excited about in the film are the French musical compositions called music concrete. They are actually made by people who have studied music and they're working not with pianos with notes, they're working with every type of sound - sometimes it's just bumps on the mike, sometimes it's a scream, sometimes it's laughter. And even though it sounds like a bunch of sounds, it's actually emotionally organized. A lot of the works are used directly from their recordings, so what's going on in the "sound design" is actually just us playing a record of somebody else's musical composition of sounds. It's magical because the artist has worked on this opus for a year so what you're hearing is a really intense work of art.

I started working the [sound] board with [Schatz] and he would make little adjustments and I would say, "Leslie, did you forget where the mid-range button was?" And he would say, "I never really knew in the first place." You realize that the really great sound guys aren't guys that know exactly where everything is.