Jay Redd heads up the visual effects team on Monster House.

We talked with visual effects supervisor Jay Redd about the evolution of performance capture on Monster House from exec producers Robert Zemeckis and Steven Spielberg. It’s the next all-CGI film after The Polar Express to use Imagemotion performance capture technology from Sony Pictures Imageworks.

Barbara Robertson: Did you use performance capture for all the characters in the film?

Jay Redd: Yes and no. We have a great cast and we’re proud of our performances on this film — there are wonderful moments from each character. But sometimes when we get into editing, we might find something would work better if it’s keyframed. What I’m excited about is that there is always a mix.

Also, this is primarily a motion capture show, but a number of characters were keyframed. There are some characters that embody human ideals but are not built like humans. For example, the house is a prominent character, a very complex, emotional creature, but it wasn’t built like a human, so performance capture wouldn’t give us what we wanted. But, because it’s an emotional character, we had an actor give us 3D reference. You get a quick glimpse in the trailer. I don’t want to spoil the film… there’s much bigger stuff that happens.

BR: Did you use the same actors for the performance and the dialog?

JR: It’s all identical. We captured voice, body and facial performances all at the same time.

BR: At the same time?

JR: Imagine yourself at a small theater on the round. We could have five or six actors on set performing together for minutes at a time. The actors loved it. Also, we’re shooting a virtual film, so Gil [Kenan, the director] could be on the set working with the actors, helping them get the most dynamic performance.

BR: It sounds like an improvement over the performance capture for Polar Express. What’s different?

JR: Technology is constantly changing; every film is a new generation. Computers get faster, cameras have higher resolution. Polar was groundbreaking because we could capture face and body, but we had to do some of it separately. We took it up a level on Monster House.

BR: In what way?

JR: We could capture more actors in the same place and our actors are playing themselves. It’s all about the stage. I worked with [motion capture supervisor] Demian Gordon, who worked on Polar and on Matrix as well. I told him I wanted to have a minimum of five actors on stage. Our motion capture stage . . . imagine a 20 x 20 foot cube 16 feet high. That’s the volume we could capture people in. On Polar, we had two 10 x 10 capture spaces. On Monster, with the 20 x 20 space we could get more detail from all the performances. We had 200 infrared cameras lined up so they could see reflected light from the markers on the actors. We needed so many cameras to see the right angles on all the actors.

BR: How long can a shot be?

JR: The more actors in the volume, the less time you can shoot because you’re feeding more data through the system — the cameras are seeing more dots. When we had one or two actors, we could shoot for several minutes. When we had six people, we might be limited to three or four minutes. Depending on the actors, we could sometimes shoot for six minutes — an entire scene, five takes. It was like watching theater happen.

BR: How many dots did the actors wear?

JR: It depended on the actor. We usually had between 60 and 80 dots on the body depending on what we needed to capture. The faces had around the same depending on which muscles moved. We did face casts of each actor and a range of emotion tests and created a set of dots specific for each actor. The facial system at Imageworks also caters to each performer. We worked with the makeup artists to create a template for precise and consistent placement of the markers every day.

BR: Did you design the characters based on the actors?

JR: Our characters are stylized — we’re not matching real people. They’re bipeds, but their proportions are different; they’re cartoon characters. Some of the characters are dramatically different from their live-action counterparts, but some of the best performance captures we have are from actors who somewhat physically match their digital counterparts.