Orchestrating the varying speeds of the game's action was one of the most challenging aspects of the sequence, notes Kidd. "The baseball game was designed to show off the vampires' speed and jumping and running abilities. They could catch the baseball without gloves when it was traveling at 100mph. So we needed to do a lot of retimes in that sequence. We'd tried to anticipate where Catherine might want speed to be in the final cut, and then we'd shoot a multiple of that shot at high speed so we could preserve our options for later. That approach gave us more frames so we could do rampings in and out of the motions if during editing she decided to use a particular take that didn't have a high-speed alternate version. For example, we could generate new frames to ramp a 24fps shot to 48fps without looking jumpy." Hancock explains, "A lot of retiming work took advantage of Shake, Chronos and Twixter, which is a retiming plug-in that does a really good job of pixel motion estimation and frame interpolation."

The climactic fight sequence in Twilight was the most complex of all from a visual effects perspective, because it takes place in a ballet studio with mirrors on every wall and pillar in the room. The idea evoked director Orson Welles' famed hall-of-mirrors sequence in Lady from Shanghai, notes Kidd. To plan this sequence, he admits, "We spent a lot of time in prep. Not only was there a lot of wire work in the sequence, but Catherine wanted to shoot it with a lot of heavy atmosphere. Light beams were pouring into the studio at night, with the rest of the studio not being lit internally."

The majority of vfx shots on Twilight were done at CIS Vancouver. ILM, Rez Illusion, Catalyst Media additionally contributed to the film. 

To prepare for the shoot, CIS did a full Maya ray-traced previs, explains Hancock. "Because of all the mirrors, we wanted to try and anticipate how many times reflections were going to show up -- whether it was of the camera crew or repetitions of the actors' reflections. Because of Catherine's shoot-from-the-hip style, we were really looking for ways to anticipate problems. It wasn't so much figuring out angles -- we were looking for what was going to be the visual effects Gotchas."

Hancock notes, "The crew was really conscious of this. They had done some of their own tests and had come up with some interesting techniques for angling mirrors and frosting them to hide unwanted reflections." Kidd explains that during prep, they tried to troubleshoot potential problems with a variety of approaches. "If we put a couple of moving mirrors in front of the camera itself, would that save us? If we created a 'mirrored box' for that camera, would that minimize the number of crew reflections? What a lot of the people on the crew weren't thinking about was that there would be so many reflections between the crew and the actors that we might have a reflection that angles backward and then bounces off another wall and is actually seen behind the camera. That's why we did the previs."

When filming was completed, Hancock said, "Occasionally we'd find reflections of the crew and equipment. What was tricky was removing the wires. Many times we were removing wires up to 3 or 4 times deep. There were a lot of cases of long shadows being cast by the wires and it was tricky to get those plates clean."

The final tally of visual effects shots in Twilight turned out to be around 250, the majority of which were done at CIS Vancouver. Kidd explains, "As the show grew we ended up doing a few shots through other vendors. ILM did a half dozen shots, in which Edward is shown in sunlight and his skin appears to be encrusted with thousands of tiny diamonds. Rez Illusion did some of the speed ramp stuff and additional motion blurring of the vampires, and my company Catalyst Media, which operates as a four wall to get things done, did about three dozen shots. There were a couple where we did some 3D augmenting, but primarily we did 2D work." Kidd used Cinesync to work with the visual effects contributors to Twilight. "We used it with all the vendors -- even the ones in L.A. -- to communicate very quickly and go over all the different shots specifically."

With Summit moving forward with a Twilight sequel, New Moon, Kidd observes, "This movie is self-contained, but there could be a setup for a sequel, At this movie's conclusion, you know there's still some bad guys out there!"

Ellen Wolff is a southern California-based writer whose articles have appeared in other publications, including Daily Variety, Millimeter, Animation Magazine, Video Systems and the website CreativePlanet.com. Her areas of special interest are computer animation and digital visual effects.