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Images
source: Troy, © 2004 Warner Bros. Pictures |
The
Greek Armada
“They were like great flocks of swans on the plain about
the waters of Cayster, that wing their way hither and thither,
glorying in the pride of flight, and crying as they settle
till the fen is alive with their screaming.“ — The Iliad, Homer
(Trans. Samuel Butler)
Very early in the process we decided that we were going to shoot
as much live action as possible. This included two full-sized boats
and a real ocean. In Wolfgang Peterson's “The Perfect Storm“, fully
computer-generated oceans were used because you cannot film real
seas at that scale, nor can you perform the type of waves that
were needed with practical, live action effects. Considering the
type of footage that we were aspiring for in Troy, we decided it'd
be far better to shoot real plates. Although this would present
a backend tracking issue, it grounded the shots realistically as
we had real oceans and environments to begin with.
There are other pros and cons of filming real boats out at sea.
The good thing is that you don't have film plates with tank edges
that need to be removed later. The downside is that you're prone
to all kinds of sea swells and inconsistent weather. Some days
we had rough seas and others were far too calm.
One of the key shots of the Greek armada has Achilles (Brad Pitt)
on the bow of a ship. The camera pulls back to reveal a few more
boats; then it pulls back even further and further, finally revealing
an armada of 1000 boats. For this shot, a camera was mounted on
a helicopter which flew for a mile, pulling back the shot as far
as possible. We knew that tracking was going to be a major issue
as nothing is stationary – the boats are moving, as are the waves.
During previsualization we planned out the shot and, with the limited
budget for visual effects, decided to use a couple of dinghies
and twelve buoys (six per boat) strung 20 meters apart from the
back of each boat. These buoys and dinghies would be the makeshift
tracking markers for the shot. As the helicopter flew further and
the buoys dropped out of view, we still had the dinghies to track
with.
On many shots, there was no horizon visible because it was generally
misty. However, the dinghies were large enough to still be seen
on the horizon. In the pull-back shot, the helicopter flew for
a mile, but they decided to speed up the footage to give the impression
of more distance. What this meant was that the tracking markers
had disappeared into nothing by the end of the shot. This was by
far the most difficult challenge, and we ended up tracking this
shot from the beginning of production all the way to the delivery
deadline as a result.
To track the sea plates, we used a combination of 2d3 Boujou
and RealViz MatchMover.
Both companies bent over backwards to help us during the project,
as it was such a tough tracking challenge. One of the senior researchers
at 2d3 wrote a new solver that really assisted us to track the
shot – particularly at the beginning where there were no buoys
visible, just the boats in the water.
Another major challenge in creating the pull-back shot was the
time constraints. The Director wanted this ready for the first
trailer. This meant that it needed to be delivered six months prior
to the deadline for the rest of the movie; and this despite it
being one the biggest shots in the film. Although the timeframe
was tight, having the boats, characters and other essentials working
raised morale and got everyone working. This shot was fantastic
for setting up the pipeline in preparation for other shots. |
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