The first sign of trouble is when the meteor showers begin in Zathura. Wireframes/shot builds: © 2005 Sony Pictures Imageworks Inc. All rights reserved. Finals: ©2005 Columbia Pictures Industries Inc. All rights reserved.

Columbia Pictures’ Zathura (opening Nov. 11) is an old-fashioned sci-fi fest, complete with a reptilian monster called Zorgon and a shiny metal robot right out of Lost In Space. It chronicles the out-of-this world events that unfold when two brothers roll the dice and play an old board game that they’ve uncovered in their basement. Zathura, directed by Jon Favreau (Elf) brings to the screen another adventure from Chris Van Allsburg, author of Jumanji and The Polar Express. And Sony Pictures Imageworks, fresh from having animated the latter film, has handled more than 200 digital effects shots for this movie as well.

Imageworks’ vfx supervisor Pete Travers, whose credits include digital effects supervision on The Aviator, Haunted Mansion and The Matrix Reloaded, explains the creative challenge given to Sony by the film’s vfx supervisor Joe Bauer. “The artwork in the book is very stylized,” observes Travers. “It’s kind of like pointillism, and it’s a very ‘50s sci-fi look. That look was a very important aspect of the effects.”

In addition to Sony, Bauer worked with Stan Winston Studios to create the robot suit and on-set Zorgon puppet. Then CafeFX computer-animated the Zorgon creature in the scene where it had to be nimble. Zoic tracked and composited star fields, and Digital Dimension also comped star fields and worked on integrating miniatures used in the film. Since there were hundreds of star field shots, Zathura was one of the season’s most heavily composited shows.

The Adventure Begins
Our first inkling that this is no ordinary board game comes when the little brother can’t read the card that he has drawn. The older brother grabs it and reads: Meteor Shower. Take Evasive Action. The little brother asks what that means, and the big brother says, “It means you have to get out of the way.” All of a sudden a meteor shower blasts through the living room of the boys’ home. “This is the first sequence that comes after the boys take a card,” notes Travers, “so the director wanted it to have a high level of energy.”

Principal photography showed the boys running around on a practical set with meteor holes already in the floor. Imageworks matchmoved the scene to create a digital camera and then added CG meteors, smoke trails, sparks and interactive glows. The trails themselves were run using a fluid-based simulation with dynamic interaction, frequently with the actors.

The challenge for Imageworks’ vfx supervisor Pete Travers and his team was to recreate the stylized artwork of the book. The ‘50s sci-fi look was a very important aspect of the effects.

The view of this chaos takes place almost entirely from the kids’ POV, explains Travers. “The director wanted this to be up close and personal. But there were exceptions. Sometimes when you’re watching a movie you’re starving for establishing shots to show what’s going on. And they are in there. The Saturn sequence is like that.”

Moving Outward
In the Saturn sequence, the film’s second major adventure, the boys discover that their house travels through space. “The kids open up the door and look out onto their porch,” says Travers, “and there’s a giant thing in the way, which turns out to be an asteroid. As the camera moves over their shoulders out into space, the planet Saturn is revealed. By the end of the sequence, you are looking at a tiny house hovering over the rings of Saturn.”

The effect was composed of a background matte painting of nebulas, and stars mapped onto a semi-curved surface. Saturn, along with its orbiting asteroid belts and moons, was built in 3D. Since the planet is gaseous, with storms raging across its surface, Travers’ team ran fluid simulations to mimic this. “We’re a big Houdini house, but we’re also a big Maya effects house. This movie was probably right down the middle. There was a lot of Houdini for meteor smoke trails and flares but there were also lots of effects done in Maya, including the asteroid belt and Saturn. But the dust surrounding the asteroid belt was done in Houdini and rendered in our proprietary renderer Birps. It gets tricky, and you spend a lot of time making sure your glue-ware is working.

“You pick and choose what will suit the shot and what the individual artist is comfortable with. Sometimes you have to pick two different packages and make sure that you’ve got glue-ware on the back end so you can composite everything together. Our pipeline for dealing with Houdini, either through Maya or coming back in through RenderMan — or even rendering out of Houdini and then compositing — is very solid.”