Computer Graphics World

June 2009 41 Digital Sets•VFX n n n n spear and his team took nearly 10,000 pho- tos in Rome using Canon EOS 22-mega- pixel cameras equipped with 8g Flash cards. "We used those to build our CG models," he says. "ey became the basis for previs, and we improved and improved them until we could use them in the movie." e previs helped Howard with pac- ing, and DP Salvatore Totino with fram- ing for shots in the huge expanse. On set the filmmakers had surrounded a replica of the base of Bernini's baldacchino, the 90- foot-tall bronze canopy located beneath St. Peter's dome, and a section of the floor with greenscreen. CIS built the rest of the baldacchino, the 138-foot-diameter dome (which rises 452 feet above the street), and the entire 694-foot-long interior in CG. e building, designed in large part by Michelangelo, covers 5.7 acres. "e previs renders were primitive, of course," says Karen Ansel, CG supervi- sor. "But, our model duplicated the entire length, so it helped Sal [Totino] know what chapel the actors might be going past." Once the crew got rough cuts back from shots for the basilica se- quences, they knew what they'd need to render and what textures they'd need. "We went back to Rome knowing the cam- era angles," Breakspear says. "We could stand almost in the same spot and take all the pictures we needed, so it was a very efficient process. Our technique is that you work out where the camera is and take pictures from there, from the end position and all the way along the in-between bits so the texture can adjust for different camera movements." Back at CIS, artists readied the photo- graphs for projection onto low-res geometry by painting out the tourists and bringing the images back to neutral lighting. "When you take HDRIs, if you have a shot with strong sunlight hitting a column, you can bring back the detail using one of the other ex- posures," Breakspear says. "It's a painstaking process. But, the meat of our work is in refin- ing those textures to be beautiful and crisp." e lighters used three setups in Maya and Mental Ray to render for daytime se- quences, dark and somber night scenes, and nighttime action sequences. "In addition to the regular ambient occlusion, shadow passes, depth maps, and specularity layers, we rendered passes with 3D lighting that worked with the projection maps to cre- ate lighting effects," Ansel says. at meant the lighters could create areas of dark and light, cool and warm, and the falloff with- out weighty re-rendering. And, if the look changed, the crew could re-render any of the 16 to 20 layers sent to compositing. In addition to the projected textures, CIS artists modeled the basilica's marble floor in 3D using detailed shaders and texture maps to create the aged tile inlays and to reflect the baldacchino, itself a fully detailed and shaded 3D model. And, light beams created with volumetric lighting and dust motes added to the atmosphere. "Technically and aesthetically, we wanted to support the suspense in the story," Ansel says. "And, we wanted to keep the basilica as inspiring in the film as it is in real life." Similarly, MPC used projected textures to create shots of the actors in the Pasetto, a secret passageway disguised as a Roman aqueduct. "We were allowed on the Pa- setto, so we photographed it using a mo- tion-control tessellator head and four digi- tal still cameras on tripods," Bickerton says. "MPC built limited geometry to project that imagery onto. And, the Senate used photo-tiling for the Pantheon, which has some fully CG shots." "Hopefully," Bickerton says, "the effects in this film are as invisible as possible. My aim was to be photographically real." And it is. After all, even though they had to film many of the scenes on soundstages in LA, they did shoot the film in Rome in a way, albeit with still photos turned into photoreal locations, thanks to the science of computer graphics and the skills of CG artists. n Barbara Robertson is an award-winning writer and a contributing editor for Computer Graphics World. She can be reached at BarbaraRR@comcast.net. CIS-Vancouver rendered the interior of St. Peter's Basilica using as many as 20 layers to create and more easily change any mood without weighty re-rendering, whether in daylight (top) or at night. At bottom, the floor is a 3D model with detailed shaders and texture maps. On set was a replica of the base of Bernini's bronze baldacchino that rises 90 feet from the floor, and a section of the floor. CIS-Vancouver built the rest of the baldacchino and the entire 694-foot-long interior of St. Peter's Basilica using CG models and projected textures.

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