'MirrorMask': Expanding the Digital Backlot

The mirror mask model created in Maya was the biggest match-move element of the film. Elements appear in the reflection and the mask was rendered with specularity for a mirrored surface. All images & © 2005 The Jim Henson Co.

For years, the subject had been at the center of many discussions. One question was asked again and again: when would it happen? Well, we now know the answer. The digital backlot was officially born in May 1996 when Paramounts Mission: Impossible was released. For the first time in movie history, an entire sequence was realized by shooting the principals on a greenscreen set and compositing them into a 100% computer-generated background. This breakthrough was made at Industrial Light & Magic (ILM) under John Knolls supervision for the final bullet train sequence. Three years later, the same ILM used the approach on a much larger scale for Star Wars: Episode I, and later, on Episode II and Epsiode III. The technique was quickly employed on many subsequent vfx movies, such as The Matrix, Harry Potter and the Sorcerers Stone and Spider-Man.

But all of these movies had benefited from a comfortable budget. The key move happened when low budget movies began to be produced on a digital backlot formula. Robert Rodriguez started with Spy Kids, followed by Immortel, Casshern, Sky Captain and the World of Tomorrow and, most recently, Sin City and Human Error. Independent filmmakers had learned to tame the technology and discovered the creative freedom it allowed them.

All director Dave McKean (left) and screenwriter Neil Gaiman started out with on the project was a digital backlot, a small budget and orders to make a G or PG-rated family film.

When illustrator and director Dave McKean was offered the opportunity to develop the MirrorMask feature (opening Sept. 30) with writer Neil Gaiman in 2002, he presumed that the digital backlot would be at the heart of the production: The Jim Henson Co. wanted to make a fantasy film in the spirit of The Dark Crystal (1982) and Labyrinth (1986). They didnt know how to do it, as they had a very small budget, maybe a 10th of what Labyrinth had cost. Producer Lisa Henson knew I had made my short films for no money at all so, she thought that might be a way to go. All we had to start with was a budget and a request to make a fantasy film that would eventually be rated G or PG. That was it! As for the rest, Neil and I had a completely blank page to begin with, which was very nice.

A Journey Into Wonderland

The limited budget dictated the general approach, as McKean knew what he could afford and what he couldnt. For example, photorealistic CG effects were out of question. Too time consuming, too costly. Because of these limitations, the script naturally grew into a fantasy adventure taking place in very stylized, very graphic world, heavily influenced by McKeans own style. My work as an artist and illustrator tends to not be realistic anyway. I work a lot with collage, using different media such as photographs, drawings, paintings and sculptural objects. Im not very much interested in realism. I prefer to be suggestive, to use metaphors. The idea that we came up with was to send the main character, Helena, into her own dream, which made for a completely surreal journey. In this fantasy world, we could do anything we wanted.

MirrorMask tells the story of Helena (Stephanie Leonidas), a 15-year-old girl working for her circus family. Unhappy with her existence, she decides to run away to go and live a real life. However, reality turns out to be an unknown word in the strange universe in which she finds herself. The kingdom of the Dark Lands is populated by fantastic creatures, from griffins to sphinxes to monkey birds. Unable to leave this world, Helena searches for the mirror mask, an object of enormous power that will allow her to wake the Queen of Light and to return home.

Just before principle photography, the budget took a big hit when plans to shoot the film digitally fell through. The technical requirements for 35mm film meant money was taken away from the vfx department. Above are the Music Box Dolls.

Originally, the plan was to use the new Viper Filmstream system to shoot the film digitally, but in 2003, the technology was not quite ready. A mere two weeks before principal photography was due to start, McKean had to switch to traditional 35mm film. This was extremely frustrating. It had a lot of impact on the production, as the original budget had not accounted for any scan work or film processing. And the money that now needed to be devoted to these technicalities could no longer be invested in the visual effects

The movie was shot on location for two weeks, followed by four weeks of bluescreen stage work. Several actors wore prosthetic make-up, but most of the characters were computer-generated, some hand-animated in Maya, others motion captured. To this purpose, a day of motion capture shoot was set up at Artem Digital, with McKean and dancer Kerry Jay performing all of the moves. Artem cleaned up the data and e-mailed it to us. Then, the animators applied the data to our own rigs and suddenly, we had walking talking characters! The data actually was very clean and needed little adjustment as it was applied to the skeletons.

Setting Up a Visual Effects Studio

While preparing the movie, McKean had realized that he couldnt afford to take the movie to an established post house. Actually, he couldnt even afford the services of the celebrated Jim Hensons Creature Shop for prosthetic work. The only way to make the movie was to post-produce it using an expanded version of the way McKean had made his short films: rent a small studio and hire a couple of versatile CG artists to produce all of the effects. On MirrorMask, the crew comprised 15 graduates who were hired straight out of Bournemouth University, a highly respected art school. They were fresh, they had great enthusiasm and, most of all, they had not yet learned the correct way of doing things. This meant that they were completely open to experimentation. I knew it was a bit risky to rely on a group of rookies to create the animation. On the other hand, I had complete control over this group, the kind of control that I would never have had with an established facility where they tend to do things their way. The graduated were selected and later supervised by Max McMullin, CG producer work on all of McKeans short films.

The visual effects were thoroughly prepared by McKean, who produced all the storyboards as well as detailed illustrations for each of the characters. The first task was to perform tracking and to match-move the live-action plates using Houdini and After Effects. We had very little tracking and match-move work to do, because I was very careful about what I filmed, and how the actors interacted with the CG world. Also, nearly every shot was locked off. So, all the camera moves were created using a virtual camera in Maya.

McKean hand-created all the textures that covered the CG models. The animators were given a lot of latitude to model the characters, to build the sets and even to light their own shots. McKean was available at all time in the same room to answer their questions and oversee their work, along with McMullin.

For the sphinxes, human faces were shot in video using high definition tape. The footage was mapped onto torn paper masks on the cats heads and animation enabled the jaws to move in synch with the mouths.

Of Sphinxes and Monkey Birds

A key element to the story, the mirror mask model, was created in Maya, based on a prop mask that Leonidas held to her face on set. It turned out to be the biggest match-move element of the film. The environment map was created from CG plates of the set and sky, while live-action elements, such as other characters, were also added if they appeared in the reflection. The mask was rendered with very high reflection or specularity to give it a mirrored, metallic feel. This was then composited over the top of the white prop mask used by the actress.

Some of the weirdest characters of the movie are the sphinxes, small cats with a human face. I made drawings and paintings of the cats, and emphasized to the modelers that they are sculptural objects made of stone and wood and paper, and not meant to be realistic. This attitude freed us up a lot to be very playful with the designs. The faces were shot in video using high definition tape. We shot the actors straight on, and then steadied the footage to have it rigidly remain in one place on screen. Then, we mapped this footage onto the torn paper masks on the cats heads. A little animation was done to get the jaws to move in synch with the mouths. The cats were all hand-animated in Maya by one artist, Paul Lee.

Much bigger, but no less surprising is the monkey bird, a human-shaped bird creature that kidnaps Helena in a scene. We had a burly prop man on set who lifted Stephanie off the ground for us. He was wrapped in blue and she was on a cable rig. Between this footage and some clever match-move animation, we made it look like the monkey bird picks her up. These creatures were animated by Jamie Niman. They were textured with albatross breast feathers.

When McKean realized that he couldnt hire an established post house, he rented a small studio and hired a crew comprised of 15 graduates of Bournemouth University. The Orbiting Giants are seen above.

The actors and the various CG creatures and set elements were combined with environments created in Photoshop. The director selected scanned images of his own paintings, photos, drawings and real objects to build original backgrounds. He then used After Effects to composite all the shots. In order to control the look of each scene, he requested the renders to be done in many different passes: the sky was one layer, then the background, the characters, the shadows, etc. It meant that the animators had a free hand in creating the various layers, injecting freshness and energy into the shots. But McKean could still bring all the elements back together and eventually make them match his vision.

McKean used Maya and mental ray as render engines. We tried a program called Smedge to organize rendering. It worked rather well, but was a little temperamental. We also used an experimental piece of software called FXCluster that was being championed by our technical manager, Dave Barnard. On this project, I found out that computers are as human as the rest of us. Dave named all the machines after different bands. The four Macs in the edit suite were named after the Beatles fair enough, I was John. But then, we needed a fifth, so he named it Yoko, and they all stopped talking to each other! Even stranger is the story of our render farm raid arrays being named after the Ramones in the hope that they would render really quickly. (The Ramones were famous for very fast-paced songs that were often less than a minute long.) They did work very quickly for very short amounts of time, and then, they would burn out and fall apart

Alain Bielik is the founder and special effects editor of renowned effects magazine S.F.X, published in France since 1991. He also contributes to various French publications and occasionally to Cinéfex. He recently organized a major special effects exhibition at the Musée International de la Miniature in Lyon, France.