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."