Luma Pictures goes croc hunting with Touchstone's "Primeval"
In one of its most technically ambitious projects to date, Luma Pictures served as lead visual effects house for PRIMEVAL, Touchstone Pictures' new horror film
VENICE, CA - In one of its most technically ambitious projects to date, Luma Pictures served as lead visual effects house for Primeval, Touchstone Pictures' new horror film. Directed by Micheal Katleman, the movie is inspired by the true story of a murderous, 25-foot crocodile that has claimed more than 300 victims, making it one of the most prolific serial killers in history. The picture opened on on January 12th in the theaters.
Luma's role on this project was to deliver over 80, complex visual effects shots for the film, nearly all of which having a full CG crocodile. Luma's artists were challenged, not only to create a digital reptile that looks and acts terrifyingly real, but also to integrate it with actors and their marshy environment. Many of the scenes involved intense, up-close action, revealing every detail of the CG model. Additionally, as the crocodile almost always appears in water, Luma's team was required to produce, an extensive array of complicated water effects, realistic enough to make audiences believe what they are seeing.The producers of Primeval considered using animatronics for at least a portion of the crocodile shots but ultimately concluded that better results could be attained through CG. "The decision to use CG exclusively for the crocodile effectively doubled our work load," explained Luma Pictures Senior Visual Effects Supervisor Payam Shohadai. "Although we have handled large projects before, this film had unique challenges. Our history of overcoming obstacles gave the producers confidence that we could succeed on such an ambitious project."
The biggest hurdle to overcome in Primeval was creating realistic water. Because the filmmakers chose to eliminate the animatronics, they were not able to shoot practical water elements during production for use in integrating the digital creature into its environments. "The crocodile is seen swimming and running through water-and mud-often in the rain," explained Vince Cirelli, Luma Pictures Visual Effects Supervisor. "As there were no practical water elements shot for the production, we had to create everything-splashes, dives, ripples, water blasts, sprays-and make it all interact appropriately with the creature, the talent and the environment."The complexity of the water effects is evident in one sequence where the crocodile has cornered several of the film's main characters. The sequence takes place in a marsh, and the creature and the actors are continuously in the water and rain, "As the croc is closing in on its prey, you can see the rain drops hitting the scales of the animal, splashing and rolling off of its skin," notes Luma Pictures Digital Effects Supervisor Justin Johnson. "We also provided CG breath, saliva and blood effects to enhance the shots."
In this sequence and elsewhere, Luma added to the gore by supplying photo-realistic digital doubles for several of the characters who are torn apart by the crocodile. "This sequence has one of the most gruesome deaths you will ever see," said Johnson "One of the characters is ripped apart as the croc thrashes its head and CG blood spills onto the mud and grass"
Creating the water effects for many of the scenes was not only an immense creative undertaking, it also posed significant technical challenges. Given the limited number of post production days, Luma had to quickly determine the best option for fluid simulations and decided on using Next Limit Technologies' Real Flow Software. "Although we have done fluid simulations before, we had not attempted it at this scale and level of complexity," added Steven Swanson, Luma Pictures Senior Visual Effects Producer. "We essentially started from scratch and built a top-notch water simulation pipeline. We purchased machines to run the simulations, tested them with Real Flow, wrote our own software to integrate the simulations into our rendering pipeline and created a number of Python scripts to extend the capabilities of the of the fluid simulation engine".Rendering the final simulations required tremendous computing resources. "Many of the scenes involved high polygon counts-in some cases 15 to 20 million polygons in a single pass with spray particles hitting four to five million points," recalled Cirelli. "Because of the high particle count of the water spray and other effects, we opted to use Pixar's Renderman to output these elements and relied on Mental Images Mental Ray software to create high quality subsurface an dielectric passes. This process added a second branch to the pipeline so we needed to develop several proprietary tools to calibrate particle attributes between the two render engines effectively."
With many of the shots requiring more than 120 separate rendered and filmed elements, Luma relied heavily on its robust compositing pipeline built around Apple's Shake Software and a proprietary SQL database back-end to track thousands of iterations as they made their way to the final shots. "The power and flexibility of Shake combined with our in house tools, built to manipulate and track elements via our SQL database, allows us to tackle these huge jobs confidently" noted Johnson
As the delivery deadline approached, Luma determined that additional computing power, beyond the initial PC-based fluid render farm, was needed. To this end, several additional workstations, in this case Intel-based Mac Pro's running Red Hat Enterprise Linux 4 and WS4 were purchased. "This way we could leverage the machines for both fluid simulations and Shake rendering on the Mac platform. As far as I know, we are the first studio to use the Linux running on Mac hardware to process fluid simulations," Swanson noted.Along with the crocodile and the water effects, Luma created several other intricate CG effects for Primeval. In one instance, artists replaced an entire bridge set, digitally, in a scene where an actor is chased by the creature. "During the process of animating the crocodile, it became clear that the practical special effects involving the bridge could not be made to match the CG crocodiles performance," observed Johnson. "As a result, we needed to replace the bridge and recreate its destruction in great detail including splintering wood planks, crocodile water splashes and impacts from the flying debris."
Luma also created an extreme close-up shot of the crocodile's eye. "Often, this type of shot is reserved for animatronics because of the high level of detail required," notes Cirelli. "However, we proved our ability to do CG close-ups on the film Underworld: Evolution, which includes several close-up character transformations. For Primeval, we developed a highly-articulated, head mesh of the crocodile complete with fully functioning inner and outer eyelids. The mesh was further augmented with high-resolution displacement maps to get extremely fine surface definition and bump maps that got down to the pore level. All told, there were approximately 28 different high resolution texture maps that went into rendering the crocodile and after displacement, the mesh topped out at over 1.2 million polygons. To really sell the shot, we added rain FX and water droplets that ran down the surface of the crocodiles skin. The result is totally believable."
Luma not only succeeded artistically in pulling off such "impossible" effects, it also succeeded from a practical point of view, delivering the entire package of effects for PRIMEVAL on time and on budget. "We always find a way to make the most of our assets and produce maximum quality with a minimum of resources," commented Shohadai. "We produce more iterations, more shots and better quality than some studios two to three times our size. We work smart and don't just throw money at the difficulties we encounter along the way. Our clients have really come to appreciate our ability to quickly develop solutions to complex problems, and keep their projects on track."
