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'The Cave': Unearthing CG Creatures

Alain Bielik does some spurlunking with the visual effects artists behind The Cave and unearthes some CG creatures.

Creature designer and supervisor Patrick Tatopoulos had to figure out what went bump in the dark. Images courtesy of Luma Pictures. © Lakeshore Ent. 

The team that brought us the innovative horror movie Underworld in 2003 is back with a new thriller. Lakeshore Ent., producer Andrew Mason, creature designer and supervisor Patrick Tatopoulos, special effects coordinator Nick Allder, visual effects supervisor James McQuaide and the CG artists at Luma Pictures are all back for a new tale focused on the exploration of a giant cave network in Romania. A group of top-notch adventurers is sent to investigate why a previous group of explorers disappeared in this maze twenty years earlier. They discover that the caves are inhabited by an ecosystem of strange creatures, including a horribly dangerous human-sized predator.

It took Patrick Tatopoulos only 10 sketches and a mere weekend to nail down the inventive design of the main creature: “There were many requirements that I had to take into account. First, the creature needed to be able to swim underwater and to fly. Then, it had to fit in very narrow places, which meant that the wings needed to fold up in a way that would not hamper the movements. Also, since the creature was supposed to move in a completely dark environment, we imagined that it would direct itself via echolocation, just like the bats and their sonar system. To this purpose, I conceived a skull whose shape was designed to gather a maximum of sounds. The head also included a specific organ to generate the sounds that allowed for echolocation. Finally, director Bruce Hunt was interested in having an exoskeleton to give the creature a bug-like look.”

Once the general concept was approved, Tatopoulos refined it by laying out the creatures outline over a photograph of its future performer in position. In order to break the curse of the man in a suit, the designer envisioned a foam latex suit in which only the upper-half would be occupied by the performer. The actor’s legs actually came out of the suit behind the legs of the creature. Covered with black or green fabric, they blended into the dark background or were simply painted out. It gave the creature a unique look that was unlike anything that had ever been done in a monster movie.

This ugly guy was referred to as the blue creature.

Delving into High Volume Character Animation

Close-ups and tight shots on the creature were initially realized with a series of suits, but whenever the character needed to fly or to perform complicated moves, CG animation was the technique of choice. Luma Pictures was called in to tackle some 200 shots with founder and president Payam Shohadai supervising the project: “We had done previous work for the production company, including on The Human Stain and Wicker Park, and so we were in consideration since the inception of the production. However, since our prior CG creature/character work was nowhere near this magnitude of complexity, there was naturally some hesitation on everyone’s part to award us the role as the lead visual effects facility, especially since Bruce Hunt had prior relations with another facility. But by the time The Cave came around, we had built a reputation as a company that could deliver, whatever the challenge. So we finally convinced the director and the job was ours.”

After the live-action plates had been tracked in boujou and MatchMover Pro, the animation was carried out in Maya. Developing the movement for the creature was one of the more enjoyable parts of the project for the artists at Luma Pictures. Since the style of the motion was not fully predetermined, animators were free to design some of the creature’s moves. These covered a wide variety of motions, ranging from flight to swimming, to crab-like crawling on the ground, to spider-like moves on the ceiling. The only guidelines provided by the director focused on specific actions that needed to happen within the shots. As for the rest, the animators had relative freedom to tie all these movement styles together and to come up with the signature moves.

The yellow creature takes a bite out of his human prey.

Low-Res Model, High-Res Maps

Luma Pictures modeled the creature in Maya, using a maquette and photographs of the suit as a visual reference. The mesh was purposely kept at a low resolution as surface details were later added in ZBrush. This was the first film in which we had a heavy reliance on a ZBrush pipeline, Shohadai explains. It took us a while to iron out the degree to which we would rely on it. We imported the Maya mesh into ZBrush and, at higher subdivision levels, we painted all the fine details, including the stringy, sinewy veins that cover the outside of the creature skin. There were so many of these that it almost looked like noodles covering the skin. We created the color map separately and used displacement maps to generate the vein map and the higher resolution details. As a result, the creature ended up having much more detail than CG creatures typically can be in films. Most important, this highly detailed CG creature was still perfectly usable in production, which is not always the case with high resolution models.

Texture maps of the characters were created in Body Paint and Photoshop. Rendering was then completed in mental ray with iRush and some custom tools developed in house. Finally, all the elements were combined in Shake with a little bit of Combustion.

As post-production progressed, the amount of CG creature shots kept increasing. Shohadai continues: Throughout the film, there is a mix of practical suit creatures and CG animation. The initial intentions were to rely on the suit more heavily than the CG creature, planning to use CG mainly in dark and mid to distant shots and the suit in close-ups or bright shots. But as time passed, the producers and director came to see how well the CG creature held up in those types of shots. They began asking for more and more CG animation in closer and more brightly lit scenarios. Not only was the CG creature holding up well in quality, but it was not constrained to the motions of an actor in a suit, allowing for more dynamic and exciting action.

In this scene, one of the rescue party members must grab hold of a creature.

A World Built in the Computer

Besides the all important creature work, Luma Pictures was also responsible for digitally extending the partial cave sets that had been built on stage at the Media Pro studio complex in Bucharest. These set extensions were created using traditional methods. First, the geometry was modeled in Maya to match the live-action set. Then, still photographs of the set were used as reference to build the texture maps that were painted in Photoshop and Body Paint 3D. Once again, mental ray was the renderer of choice.

In many cases, especially the very wide shots, the major part of the environment was computer-generated. When the camera move allowed it, the set was created as a matte painting but, more often than not, 3D and 2 1/2 D enhancements were required. When the camera move implied a small perspective change on the environment, we rendered still frames of CG stalactites, columns, or stalagmites that we then projected onto multiple CG cards, Shohadai comments. We developed some tools that allowed for the proper lens distortion. When the camera move was too extreme for the CG card technique, every single stalactite and stalagmite had to be modeled individually. Luckily, we had a pretty efficient mental ray pipeline that let us work with low resolution meshes that were later displaced in the render.

The climax of the movie takes place in one of the larger caves the methane cave which is a volatile environment with noxious gases and explosive fire plumes. For this sequence, a large set was built on stage to shoot the action and the physical effects. Later on, CG environment artists extended the cave formations upward and outward to increase the apparent size even more. Fire elements were created and rotoscoped from the live-action plates to further enhance the shots.

More shots of the yellow creatures in all their gruesome glory.

Entering A New League

Altogether, Luma Pictures had approximately four-and-a-half months from receipt of the majority of film plates to complete the film, with a few months of R&D and modeling before that. The Cave was our biggest endeavor into organic CG creatures for film at that time, Shohadai concludes. Weve since been working on far more CG character animation for the upcoming Underworld: Evolution. However, in many ways, The Cave was the most impressive work we had completed till then. The creature had a lot of intricate details and a wide range of motions, not to mention that about half of our shots had some sort of CG set and that all this was realized on a small post budget. Im mostly proud of the quality we produced on these 200 shots with a staff of only 45 on such a tight schedule. For a company of our size, I think it puts us in a pretty unique league to have the talent and expertise to do entire feature films that are so CG creature heavy. Our success on this film has created a number of opportunities for us to work on more challenging projects and were all really excited about the direction that Luma Pictures is heading.

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 that opened Feb. 20 at the Musée International de la Miniature in Lyon, France (www.mimlyon.com). Displays include original models and creatures from 2010 Odyssey Two, Independence Day, Ghostbusters, Cliffhanger, Alien Vs. Predator, Alien 3, Pitch Blackand many more. The exhibition runs through Aug. 31.

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