Inside HBO’s Rome: Digital Blood, Bodies and Buildings

When heads rolled in ancient Rome, it was a spectacle. Blood flowed in the Forum. Authentically but invisibly recreating the violence in the Empire for the BBC and HBO’s $100 million miniseries required a different kind of bloodletting-from gutsy VFX crews who turned CG body parts into believable street fights and particle effects into splattering blood.

"Rome was brutal," says visual effects supervisor Jim Madigan. "We had to sever heads, stick CG knives through people, and add blood. And there are a lot of shots with people having sex, so we had to remove G strings and add body parts."

The 12 episodes of Rome feature 350 VFX shots, many of them involving set extensions, crowd replications and fix-its, as well as others of a more visceral nature. During a gladiator sequence, for example, the gruesome effects included a close-up decapitation. "The blood was tricky because when it squirted out of a neck, it ricocheted off the shield, flew through the air, and splattered on the head and the ground, which was being dented by the head," Madigan says. A system set up in Next Limit’s RealFlow particle and fluid simulator mapped a shiny red texture on to the UVs of a surface as soon as the blood touched it. Several rendering passes for subsurface scattering, ambient occlusion, specular highlights, shadows, and so forth helped make the head, created with Pixologic’s Z-Brush, and the torso, created in Maya, believable.

Beyond the bloodshed, there were issues of sheer scope. Production for the miniseries took place on five acres of backlot and soundstages built in Rome’s Cincecittà  Studios, where a Forum set approximately 60 percent the size of the original Foro Romano was built. Of course, that wasn’t large enough.

"The truth is, no matter how big the set, it’s still not going to be as big as the city of Rome," says Joe Pavlo of The Senate, which acted as the in-house facility for HBO during production in Rome and handled most of the post-production, including about 80 percent of the effects. (Pavlo was visual effects supervisor during filming from February to November, then handed the reins to Madigan.) "The series isn’t about the city and the views. The style was more like a documentary – we were shooting people in the street. We’d add hills and temples in the distance, but you might get just a glimpse."

Even so, putting Rome in the background meant modeling the entire city. "We used ancient topographical maps," says Madigan. "Rome is incredibly well documented, and foundations for most of the temples are still there, but the valleys were deeper and the peaks were sharper then."Because the set was an idealized version of the Forum built for good camera angles, the crew made a 3D replica by Lidar-scanning the entire five-acre set. That replica was then shouldered into their more accurate 3D model of ancient Rome.

Once done, the crew could place a virtual camera in the 3D model and see the view from various characters’ houses and hilltops. "You could see Pompey’s garden from Caesar’s garden," Madigan says, "and the Forum set from Atia’s garden. Sometimes we’d use the actual view, but other times we’d idealize the view to give a better feel." When possible, they created the view with matte paintings. However, camera moves often made fully textured and rendered 3D buildings necessary.

In addition to The Senate’s Rome, visual effects crews at London’s Cinesite added tents to Caesar’s camp, and Rushes, another London VFX house, created the port for Caesar’s arrival in Alexandria. "We had a foreground piece of sand," Madigan says. "Everything else was bluescreen." That included Egyptian buildings, the famous Alexandria lighthouse, two meters of pier, CG water, and CG boats with sails rippling in a SyFlex breeze.

For Pompey’s wedding, working with 20 extras, Madigan shot groups of three that he put onto cards facing camera view, and then slipped in motion-captured digital doubles to add complexity. "We balanced the fill to the key on the digital doubles to match the people shot on the day and they fit in really well," he says. But more often, he used people filmed on blue screen rather than digital doubles.

"The producers, god bless them, gave me three days of blue screen and as many extras as I wanted," says Madigan. After the series had been edited, he combed through the footage to pick out likely scenes and note the lighting direction, then filmed costumed extras in lighting to match. "We got the kind of realism we could never get out of generic motion capture."