'The Messengers': Invisible VFX For Creepy Shadow Game

If you have the QuickTime plug-in, you can view a clip of the vfx in The Messengers by simply clicking the image.

Children should always listen to their parents, but there are certain circumstances where parents should listen to their children. In The Messengers (which opened Feb. 2 from Screen Gems), the Solomon family has left the hectic life of Chicago for a quiet North Dakota farm. The idyllic setting soon turns into a nightmare for Jess, 16, and her little brother Ben, when they both begin seeing horrific specters that remain invisible to everyone else. When the ghosts become violent, Jess and Ben can't even get help, as nobody believes them...

To create some of the scariest moments in the movie, directors Danny and Oxide Pang (The Eye) turned to visual effects supervisor Bruce Jones. "We produced about 150 vfx shots, of which 120 ended up in the final cut," Jones recalls. The visual effects were primarily produced by Technicolor Creative Services (supervised by Brent George), Reality Check Studios (supervised by Kory Jones), Michael Kaelin & Associates (supervised by Michael Kaelin) and Amalgamated Pixels (supervised by Derry Frost). "We had a wide range of visual effects to create, including digital birds, CG dirt, greenscreen composites, digital make-up and matte-paintings," Jones continues. "The directors were very specific: they didn't want any shot to stand out as a visual effect shot. Everything had to look real, especially the scenes involving real elements such as the birds."

Shadow Game

The ghosts first appear as a mere shadow, a creepy silhouette that could be human... or something else. Created by Amalgamated Pixels, the shots required a 2-1/2D approach. "We first shot the live-action plate," Jones explains. "Then, we filmed the shadow of a performer on a white sheet. Once the plates were tracked, the 2D shadow element was projected onto a 3D geometry of the set, allowing for the shadow to realistically flow over the walls and furniture."

Soon, a three-dimensional creature appears to the children in the form of a ghost boy who crawls up the walls and on the ceiling. "We shot a clean plate on the set. Then, we built an inverted set representing the basic geometry of the live-action set, all covered with greenscreen material. Using video assist, I lined up the greenscreen shot with the clean plate, in order for the perspective to match. It actually required a good deal of thinking as one of the sets was upside down, which made the lineup process a little more complicated than it usually is. We didn't employ any motion control on this project. Whenever the camera had to move, we carefully timed the amount of seconds it took from point A to point B, and later shot multiple takes in order to closely approximate the same movement on the second set. With powerful tracking tools such as boujou, we managed to make it work. The ghost boy was shot on the inverted set, often rigged with cables to allow him to crawl down the walls. Once composited in the clean plate, it looked like he was crawling up the walls."

The ghost boy makes his first appearance as a reflection in a spoon that little Ben is looking at, a key shot handled by Technicolor Creative Services, a company formerly known as Toybox/Command Post. "We produced a total of 26 shots, most of them requiring 3D work," notes vfx producer Persis Reynolds. "The spoon shot is actually a combination of several elements: a plate featuring a real spoon, a CG spoon covering the real one, a live-action plate of the actor playing Ben that was inverted to appear upside-down as a reflection and a greenscreen plate of the ghost boy on the ceiling. The two plates were projected onto the CG surface to be warped and distorted by the curved geometry. The elements were then composited with Shake, our primary compositing tool."

Even more disturbing is a scene in which Ben watches his mother making the bed. As she throws open a sheet to set down on the bed, the little boy sees a pair of legs under the sheet, as if there was a woman standing on the bed, in a pool of blood, facing his mother who doesn't notice anything. "This was one of our favorite shots," Reynolds observes. "We had a plate with the actress throwing the bed sheet open, and a second plate with the ghost lady standing up on the bed. Using the edge of the bed sheet as our matte line, we combined the two plates with the sheet revealing, and then masking, the ghost's legs. We also created a small matte painting representing a pool of blood that we added around the ghost's feet. In order to make sure they had the right look, our matte painters poured fake blood over several pillows and sheets, and stepped on it with their bare feet!"

Taming a Flock of Crows

The major part of Technicolor Creative Services' contribution to the movie involved creating a menacing flock of crows. Live trained birds were used in many shots, as well as some hand puppets, but when the action required a direct interaction between the crows and the characters, or when a huge number of birds had to fill up the screen, CG animation was employed. "We had about 20 shots featuring computer-generated crows," says technical director Gene Dreitser. "We spent three to four months building our CG models, using a hybrid pipeline. The models were built, rigged and animated in Maya. Then, we used a custom set of export plug-ins that took the animation into Houdini where we did all our lighting, shading and effects work. Rendering was handled in Mantra. We spent months analyzing reference footage of birds in flight to ensure the internal rigging was extensive enough to produce realistic movement from every part of the model. In Maya, we only modeled the hard surfaces: the beak, the feet, the flight feathers and the body. At this point, it was essentially a naked bird. The feathers were added in Houdini after animation had been completed. They were handled by a separate team whose primary focus was feather collision for realistic feather flutter and movement."

Three different models were built: a very high resolution model for birds appearing up close, a medium resolution bird for mid-ground action and a generic low-resolution model for the flocking shots. In most of the shots, the team had six or seven "hero" birds that were hand-animated to appear in the foreground, often in direct interaction with the characters. The background birds were animated via a particle system. "We built up a library of about 100 different flight cycles and actions," Dreitser explains. "When we were setting up the particle system to simulate flocking motions, I would assign a cycle on a bird, depending on its intended action in the shot. So, if we had a bird diving, the program would automatically select a cycle from our library of diving cycles. The particle system was 'guided' by very articulated paths, which allowed us to precisely control the general movement. We didn't include any physics-based parameters in the system because I felt that it was adding unnecessary constraints on the animation. We had a tool that separated the birds out and made sure that they didn't intersect with one another. This tool also introduced random variations in each individual bird."

Lighting the crows was an issue as it turned out to be difficult for the details to properly read on screen. To avoid rendering a mere blurry black shape, the team created custom illumination models that were able to simulate the micro-facetted highlights of the real bird's feathers. The highlights were then adjusted in compositing to match reference footage of live crows in flight. When the CG birds had to interact with a character, the team built and match-moved a stand-in human geometry on which accurate bird shadows could be cast. The final shot featured some 650 CG crows, necessitating the use of a delayed load archive technique: the geometry and all its associated shaders were not loaded until they were actually needed. With this approach, the render time-per-frame ended up being roughly seven minutes.

Birds on a Greenscreen

Although the CG birds were featured in all the key shots, Jones was able to obtain spectacular action by compositing live crows into live-action plates. "We shot tons of crow footage on greenscreen. We even shot against a blue sky. We were later able to key it out and drop the birds in another plate. For shots featuring a large number of crows landing or standing on a rooftop, I simply combined several plates of real birds landing in front of a greenscreen, shot from the proper perspective. There was a scene in which the birds attack one of the characters in a field. To show them actually picking and biting the character, I had one of the trainers all dressed up in green with pieces of chicken attached to his body. He was shot in front of a greenscreen, mimicking the movements of the actor in the original plate. The crows would fly around him, trying to grab the pieces of chicken. It was very impressive to watch. Then, we lined the crows up with the real actor, and then tracked and composited them in. In the final shots, it looks like they really are attacking him."

As if ghosts and crows were not enough, the characters also have to deal with the ultimate threat: a basement that comes to life in the form of dirt pushing through the wooden boards and acting like a living creature... "During the course of the movie, we find out that the bodies of the ghosts are buried underneath the basement," Jones says. "When Jess comes down, the ghosts use the dirt to try and grab her. We worked a lot with Reality Check to establish the proper look for the dirt: it had to flow realistically, and yet have a supernatural quality to it. The process began by shooting practical elements of mud over greenscreen. We then used a combination of displacement and bump maps that were derived from a particle solution, based off of sprites created from the practical footage. The floor was reproduced as a 3D geometry and match-moved using boujou. Particle fields were then employed to control and direct the CG mud flow. They used Maya for particle animation and rendering, and After Effects and Shake for compositing. Along with the crow attacks, this was one of the sequences for which I feel the visual effects added a lot of production value to the movie. This was also true for the ghost sequences. The performers wore great prosthetic make-up, but we enhanced it with 2D techniques. I also had the idea to shoot the plates at six frames-per-second while the performer moved in slow motion. It gave us a jerky motion that added a unique quality to our ghosts. Altogether, I really think that we exceeded the production's initial expectations for the visual effects."

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 Cinefex. In 2004, he organized a major special effects exhibition at the Musée International de la Miniature in Lyon, France.