Multimedia
Newsletters
Blogs
Whitepapers
Events
DCP Directory
Mill Directory
Edit Calendar
Advertisers
Reader SurveyStep by Step: The Chronicles of Riddick
Aug 1, 2004 12:00 PM, By Ellen Wolff
When Universal Pictures continued the saga of Pitch Black with The Chronicles of Riddick, director David Twohy was again at the helm, with definite designs in mind for the film's fantastical worlds. Twohy wanted to reveal the sinister style of a conquering Necromonger army with a “promenade shot” where Lord Marshal (Colm Feore) walks down an avenue of spaceships. These, of course, were no ordinary ships: animated in photoreal CG, they revealed “faces” when their leader marched past them.
“The ships resemble warriors bowing to the Lord Marshal,” explains visual effects supervisor Peter Chiang. “Their textures kept the dark, sinister feel by being represented with iridescent colors, a kneeled steel look.” Everything about the tracking shot had to suggest the dawn of a bad day on a vanquished planet.
Handling the assignment was Los Angeles-based Hammerhead Productions, led by visual effects supervisor Jamie Dixon. Chiang provided concept illustrations and a low-res previz done in NewTek's LightWave, and then Hammerhead created more detailed previsualizations in Alias Maya. These were shared with Feore in preparation for the greenscreen shoot. “So it was fairly clear to him what was supposed to be going on,” says Dixon.
Filmed by first unit DP Hugh Johnson, the greenscreen environment contained tracking markers, which Hammerhead would later use to track the computer-animated ships into the shot. For tracking, the studio used its own Academy-honored Ras Track software.
Meanwhile, Hammerhead's 3D supervisor Paolo Moscatelli was devising the animation for the ships' menacing-looking faces. “Paolo had the idea that a face could be extruded through the grill of each ship,” Dixon says. “We made it very much like a puzzle — or a Transformer toy — where one part of the face slides forward and the other part rotates into position. It doesn't really click together into a complete image until the very last moment. You see this big mechanical event happening, and then boom, it's a face. It lent a dramatic touch to an otherwise mechanical motion.”
All the animation was done in Maya running on Linux-based PCs.
Hammerhead also used the procedural animation capabilities of Maya to create an anti-gravity effect associated with the Necromongers' ships. “There's black, warped material that's kind of the opposite of exhaust,” says Dixon. “When the ship is in motion, that black material is actually sucking into it — it's not trailing behind like normal exhaust would.”
Effects animator Brian Lutge used a particle system approach to create the effect, which Dixon describes as basically like a bunch of strings hanging behind the ship. “The strings were made up of little dots that were actually pulling into the ship to get that inward sucking effect, and they were naturally waving behind it.” To give this atmospheric effect a bit of density, Hammerhead used a distortion field and moving noise patterns. “[It's like] the stuff you see above a candle flame because of the difference in density of the air there,” Dixon says. “Later in the shot, that ripple goes across the face of the warrior ship. It's very subtle stuff.”
One of the most challenging aspects of the assignment was the complex lighting it required. “David Twohy wanted the ships to reflect worlds of saturated color,” Chiang says. “The reflective quality on the surfaces took on the environment, and the rainbow colors represented by the ships' iridescence helped give them scale. Hammerhead designed the textures so that the outer edges of the specular areas would take on an additional map that represented these additional colors.”
Hammerhead created the gunmetal-looking surfaces using Pixar's MTOR and RenderMan software, writing custom shaders to achieve a convincing look.
“They were rendered in floating point to avoid clipping highlights, and each of the separate passes [diffuse, specular, ambient, reflection, shadow matte] were output as well,” Dixon says. “The gravity element was also expensive to render and was output in red-green-blue layers to give the compositor maximum flexibility without need to re-render.”
Lead compositor Justin Jones explains, “The red channel, for things closest to the ship, got turned into the black-looking material. The blue channel was a little bit larger and that was used to tweak the background and make it a little brighter. And the green channel was a very large pass that went far behind the ship and above it, and that was used to do the displacement — a slight blur and distortion.” This approach was designed to provide Jones with the greatest flexibility during compositing, enabling him to dial things up and down as needed.
During compositing, which was done using Apple's Shake software, Jones had to integrate the computer-animated and greenscreen elements with matte painted skies that reflected DP Johnson's lighting. These paintings were done at Hammerhead using Adobe Photoshop running on Mac OS X machines. What made the integration process tricky was the dawn light in which the shot unfolds, Dixon says. “Typically that kind of lighting is warm, so we spent a lot of time figuring out how to use this warm orange light but still maintain an ominous mood.”
Real life intervened at this point, in the form of L.A. wildfires. “From our offices we could see horrible black skies in the early morning, and we shot lots of reference photos of what that looked like,” Dixon recalls. “In the background of our shot we also have black clouds that are kicked by a pinkish-orange light. That light kicks into the warrior ships as well.” Chiang says these photo references were “right on.”
Final touches included hand-tweaks that were basically articulated mattes, which let Hammerhead add subtleties like highlights on the actor's face. “It turned out to be easier to do that in compositing rather than going back and re-rendering,” Dixon says. Hammerhead's own Roto software was used for doing these mattes and for cleaning up the greenscreen footage.
The result of watching these bowing, menacing machines, Dixon believes, “was kind of creepy — to good effect. This was in-your-face 3D.”
| Director - | David Twohy |
| DP - | Hugh Johnson |
| Visual Effects Supervisor - | Peter Chiang |
| Shot Design - | Matt Codd |
| Previsualization - | Daren Dochterman |
| For Hammerhead - | |
| Visual Effects Supervisor - | Jamie Dixon |
| Lead Compositor - | Justin Jones |
| 3D Supervisor - | Paolo Moscatelli |
| Matte Painting Supervisor - | Carlos Arguello |
| Effects Animator - | Brian Lutge |
| 3D Look Development - | Aung Min |
| 3D Lighting - | Jason Yanofsky |
| 3D Modeling - | Michael Meyers |
| Animation - | Alexander Vegh |
| Shader Writer - | Brian Gardner |
