BY CAMERON NEILSON
FROM ESC ENTERTAINMENT
The
Burly Brawl was originally conceived by Larry & Andy
Wachowski, but it would take a huge effort to create the finished piece
from a rough
concept. The sequence was first roughed out as a series of storyboards
that illustrated and blocked out the action. With these conceptual drawings
as a starting point, the process began to bring the Brawl to reality.
ESC Entertainment (who did the Visual Effects for the Burly Brawl sequence)
realized early on that the task of creating multiple Smiths would require
many
shots
to
be created
entirely
in the computer using synthetic humans and virtual backgrounds. While
much of the sequence would be created digitally, there were still many
live-action shots, so matching the look of the two was imperative. To
accomplish this, ESC worked closely with Production Designer Owen Paterson,
Director of Photography Bill Pope, and Visual Effects Supervisor John
Gaeta (among others) to ensure that the virtual environment would match
the live set as closely as possible.
A lidar scan of the entire set was created as a reference model for recreating
the geometry in the computer. Photographs of the lit set were taken both
as reference and for use as virtual background textures. A technique
known as Image-Based Lighting (IBL) was used where chrome balls are photographed
in order to capture and replicate the on-set lighting.
With both the practical and virtual sets complete, work could turn toward
the actual choreography of the Burly Brawl. The first step was for fight
choreographer Yuen Wo Ping, the Wachowski Brothers and John Gaeta to
plan out the action of Neo fighting the many Smith copies. The complex
choreography was then input into the computer using a motion capture
setup. Since the scene involved dozens of people, it had to be broken
down and captured a few people at a time, and then rebuilt afterwards.
The mocap data was then mapped to the corresponding Neo and Smith models
and the animation imported into Maya.
Working from this initial mocap animation, John Gaeta and the Wachowskis
then worked with ESC to refine the action. Using low resolution models
and virtual background textures, the animation team cleaned up and modified
the imported animation by hand. At the same time, this pre-vis setup
was used to adjust the camera moves to best frame the actors in each
shot.
Now that the animation was complete, the process of recreating Smith
and Neo began. Each actor’s likeness, facial expressions, skin
tone, and clothing all had to be recreated and simulated in the computer
in photo-realistic quality. A process called Universal Capture (UCAP)
was developed to capture and recreate each actor’s head and facial
characteristics. Five high-definition cameras and a small army of computers
were set up to record the various facial expressions of each actor. The
amount of data collected was so immense that each day’s work was
backed up every night by a robot tape system. Combined with a cyberscan
cast of each actor’s head, the Universal Capture information allowed
ESC to create an exact moving replica of each actor’s head.
To simulate the appearance of cloth and its interaction with light, the
wardrobes for both Neo and Smith were scanned using a Bidirectional Reflectometer,
which captures the light reflectance (Bidirectional Reflectance Distribution
Function or BRDF) values for all kinds of cloth. Using this extremely
powerful machine allowed ESC to scan the various types of cloth involved
in the actors’ wardrobes, which could then be recreated and simulated
in the computer.
Combining the Universal Capture data, facial casts/scans, BRDF information,
and light characteristics through IBL, a virtual human is created. Side
by side tabletop comparisons of the real Smith and the virtual one yielded
practically indistinguishable results. The facial performances from the
UCAP sessions were then assigned to the heads of Neo and the many Smiths;
and for the final touch animation was added to the actor’s virtual
clothing to simulate realistic movement.
All
pieces complete, the final synthetic human animation is composited
with the finished virtual background to create the final shot. Before
rendering out a given frame, each shot exists in the computer as lines
of code, millions of assets compressed into one final shot.
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