'Zoom': Superheroes + Feature Film = Big VFX

Just like Galaxy Quest was playing the Star Trek mythology for laughs, Zoom is a comedy playing with the superhero frenzy. Both movies have Tim Allen as the reluctant down on his luck hero. In Zoom (released by Columbia Pictures on Aug. 11), he portrays an out-of-shape former superhero who has lost his powers. He must now teach a group of unwilling teen superheroes how to control their special skills and ultimately how to save the world.

As with any superhero movie, visual effects played a key part in visualizing the special powers of the characters. To this purpose, director Peter Hewitt turned to Digital Domain and to visual effects supervisor Mark Forker. In charge of producing some 280 shots, the team also included vfx producers David James and Todd Isroelit, digital effects supervisor Serge Sretschinsky and CG supervisor Johnny Gibson.

The script called for six different superpowers to be created via visual effects. One of the four teens, Tucker, has the ability to grow enormously fat, a talent that he learns to control as the movie progresses. Reminiscent of Eddie Murphys Nutty Professor vfx, the growth effect was primarily realized via 3D animation, with the first stage being created with a 2D morph. We just shot the actor playing the scene on set without any blue screen, Sretschinsky says. Since we were going to add body parts that were bigger than him, it was pretty easy to cover him over. For one thing, we never had to worry about getting clean plates. We started with a basic CG model of the actor that we built in Maya from a cyberscan. Then, since a different part of Tucker grows fat in almost every shot, we had to build a specific model for each scene - a foot, a head, an arm, etc. One issue that we had to address was the way the skin textures stretched. For shots where his body parts grew really large, we had to paint separate texture maps. It was actually quite challenging because the actor was a young kid with a smooth and clean skin, which meant there wasnt a lot of detail for us to play with. So, we ended up adding pores and color variations that were not part of the original skin textures. It had to be subtle because if we went too far, he would look like an old man

The CG elements were rendered in RenderMan, the renderer that was used for all the characters effects, with a subsurface pass and conventional skin shading. The various layers were then composited in Digital Domains proprietary Nuke system, with Paul Kirwan acting as compositing supervisor.

Now You See Him, Now You Dont

For Dylan, a character with the ability to become invisible, Digital Domain favored a 2D solution. The shots were basically created in Nuke, Sretschinsky says. For every shot, we had a live action plate and a clean plate. Since we didnt use motion control, we had to reproject the clean plate in order for the camera move to match the motion that was performed on the live-action plate. We then developed a Nuke script that took the image of the actor and brought other parts of the background in to create a distorted glass effect during the transitions. The challenge there was that we wanted to use exclusively 2D elements to create a three-dimensional effect. The key was to design a specific progression of how the body appeared or disappeared. Very conveniently, the costume became invisible with the character

The challenge was different with super strong seven-year-old Cindy, a character who mostly necessitated wire removals. During principal photography, the actress was shot lifting or throwing heavy objects that were in reality animated with wires. Although the approach worked fine in most cases, there were shots in which the object didnt look heavy enough, and other shots where one could feel the presence of the wires. We put a lot of effort in to reanimate the object, Sretschinsky notes. We first had to isolate it from the background, and then put a different rotation on it, so that the whole motion felt more realistic. In some instances, we used the original object and manipulated it in Nuke. In other cases, it was built in Maya and animated. Similar effects were required for Summer, the telekinetic girl. Again, real objects were moved around on set with wires, or CG replicas were animated in the computer.

For Zoom, the script required several shots in which the character vibrates his body before getting to super-speed. Allen was first isolated from the background and his body was manipulated in 2D. For shots where the character was running super-fast, a hybrid 2D/3D solution was employed. Allens image was projected onto a 3D model and the animation was mixed with a motion blur created in Nuke. Later on in the movie, Zoom runs into a big circle, generating a giant vortex. The 3D effect was primarily created in Houdini, but Digital Domain also used STORM, the proprietary volumetric system that had already been used to great effect for the tornadoes in The Day after Tomorrow and for the clouds in Stealth. First, we created the animation in Houdini, Sretschinsky explains. The animation basically drove where the voxels would go. Once we had the skeleton of the motion, the STORM system was used to generate the volume on top of that skeleton. The resulting images were rendered in STORM.

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We also had a shot where Zoom runs in the desert and falls down. The environment was actually created from dozens of tiled still photographs of the real location. When the shot was changed in post-production, we ran into a resolution issue: our tiled background didnt have enough resolution for us to zoom in on the character as requested. We had to spend a lot of time refining it in Photoshop and Nuke to make the new camera move work. In this particular shot, Zoom was created as a 3D animation.

Energy Issues

Zooms arch nemesis is Concussion, a man with the ability to throw powerful energy waves. The character required two types of effects. First, there was the beam itself, a CG distortion effect developed in Houdini. The basic animation was a series of energy waves traveling out and distorting the air as they fly across. We looked into adding extra layers to the distortion, such as light or electrical components, but it was eventually decided to stick to the plain energy wave, Sretschinsky observes. The most difficult aspect of the effect was when the action was taking place in front of a relatively featureless background, in which case the distortion would become hard to see We had several layers of animation: the shockwave at the front, the various discs that followed it, plus extra distortion effects. They were all rendered in Mantra. Since we didnt want to use ray tracing, we spent a lot of time trying to get a feeling of depth out of the animation. A lot of it was created in Nuke by tweaking the various layers. Animators also had to create the impact of the energy beams on the environment. For the climax that takes place in a quarry, the devastation was realized with a combination of practical effects and CG animations created in Houdini. Nuke was then utilized to maximize the impact of each energy blast.

Besides creating the special power of each superhero, Digital Domain also produced a great deal of set extensions. One of Nukes most interesting features is that it has a full 3D system built into it, Sretschinsky notes. A lot of the set reconstructions and extensions that another house might have done with a 3D package were rendered with Nuke natively. We did have a fair amount of set extensions to do. The main hangar, in particular, was greatly extended via a combination of 3D elements and 2D tiled photographs. The live-action set didnt have a ceiling. So, we created it using mental ray and full global illumination. On the other hand, the spaceship that is stationed in that hangar was modeled in Maya and rendered in RenderMan. In the same series of shots, we also had a CG double of Zoom with hair and cloth simulation created in Maya hanging off for dear life underneath the spaceship. The trickiest part of the sequence was when the hangar doors open and let the bright Nevada sunshine in. The difference in light level between the interior and the exterior was so extreme that we had to render the two environments separately. In reality, the part of the image showing the outside would have completely blown out. So, the shot was first rendered with the regular hangar lighting, and then rendered again with the exterior light coming through the doors. Our compositors later managed to combine both elements to create a seamless and pleasing transition.

Additional Work

Although Digital Domain created the bulk of the work, additional visual effects shots were assigned to Luma Pictures and Custom Film Effects. At Luma, the project was supervised by co-founder and visual effects supervisor Payam Shohadai, with CG supervisor Vincent Cirelli. We completed about 80 shots, Shohadai says. Half of our work was basic 2D compositing type work, plus their related design components, and the other half was relatively basic 3D animation. We did a series of shots where a character dissolves a CG apple through mind control. In another scene, a different character rearranges a CG generated engine component to a spaceship. We also had a paintball training sequence in which the four heroes are being bombarded with a large amount of CG paintballs.

Sretschinsky concludes: I had done other superhero movies before, including X-Men 2 and even Judge Dredd, back in 1995! On Zoom, we really had a good time doing it. It was a very well run show. Some of the work was very challenging, and, for the rest, it was the usual amount of blood, sweat and tears

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