"We took the catapults and made two into 10 or 12," Nelson describes. "The practical catapults wouldn’t fire far enough, so we also put in CG flaming pots. Ultimately, when we got into post, we sewed all of those plates together. We slip-synched all of the elements so they were going off at the right time, meaning the explosions were happening, all of the people were marching at the right time, et cetera. We placed a blend line between the different tiles of marching soldiers and added thousands of CG flaming arrows. When it was all said and done, we had this big, long tile that was all sewn together with the lens distortion for each tile taken out. Then we did a virtual move through the sewn-together tiles and added lens distortion back on, so we had one uniform lens distortion throughout the move. Tim Burke, a visual-effects supervisor at Mill Film, came up with the triple tile technique. Originally I thought of doing an oversized plate and doing a limited pan, but once we started thinking of it in three separate tiles, we could get a dynamic pan from one side to the other."
In the warmer confines of Malta, the grandeur of Rome was displayed in another complicated tracking shot known as the "Blimp Shot," which tracks over the entire, digitally expanded cityscape set up to the centerpiece of Rome the Colosseum and then over the top of the Colosseum, with a bird’s-eye view of the combat action staged on the arena floor.
"Naturally, we were shooting off the set, where you could see the ocean, cars, wagons, et cetera," says Nelson. "The sets were never originally constructed to be photographed from that angle. We had to work out the move and know what height we needed to shoot plates from because we were shooting a Colosseum that didn’t yet exist. We worked it out by previsualizing the move extensively, then shot it with a VistaVision on a Wescam mount. Later, we added thousands of motion-captured people to augment the real people, added building tops and additional structures to the Roman Forum, extended the exterior of the Colosseum up two levels, built the interior of the Colosseum, populated the interior and placed a fight on the floor of the arena. You see 500-600 slaves manning the roof. It’s a pretty incredible shot, with many people who worked on [it].
"The velarium [a massive, canvas roof that shaded the audience] on top is a 3-D computer graphic extension," he continues. "The people running around on the velarium were done via motion capture. We had people doing roof-slave actions, such as lifting, cranking, walking, talking and pointing. We took still pictures of extras, mapped them onto 3-D people in the computer and animated them with the motion-capture data that we got from the motion-capture recording. They were duplicated into how many we needed for the roof, and then they were rendered with the light in the same place as the light in the real photographic plate.
"One of the many good things about Malta is it’s a Roman town in many ways; it has things like aqueducts, huge walls and fortresses. We used these as backdrops or as elements. We would go out and shoot them individually, then put them back in. If we couldn’t find 2-D solutions to the elements anything we could photograph then we would just build it in 3-D and light it. We also had matte painters; if we found there was no perspective shift on things in the background and we couldn’t build it or photograph it, we would paint it. We got a lot of great stuff from Malta, but it needed to be augmented."
The details of designing the interior of the Colosseum, particularly those regarding the shadows cast upon the audience by the velarium, were the subject of lengthy preproduction discussions among all parties. The consensus was that digitally creating shadows for every crowd shot would be inappropriate. Confesses Nelson, "You can do stuff with tone mattes, where you take the highlight on the key side build it up and take the fill side and crush it down, but it never really looks right. Plus, it would have added a tremendous amount of money and upped the amount of shots. Ridley wanted the shadow in tons of shots. He really liked the idea of the way the velarium gave the arena this dramatic, theatrical lighting by cutting swathes of light and shadow through the audience, so for the shots that did not go off the constructed set, we cast shadows from a practical ’mini-velarium’ on the top of the set."
[ continued on page 3 ]