VIRTUAL PRODUCTION TECH
DRIVING CREATIVITY MARS Volume makes the most of virtual production for in-car scenes in Season 2 of Gangs of London, blending reality with the digital world
be seen before dissolving into dots or shimmering interference patterns. Some displays have more resolution than the images displayed on them, just to avoid moiré. Displays need calibrating so the panels don’t look like a chequerboard of almost-matching images; processor manufacturers such as Brompton provide devices to handle that. If we want the on-screen image to react to camera position, we need to involve camera tracking – whether that means markers on the main camera with tracking cameras around the studio, or the reverse. The GhostFrame system cleverly displays tracking markers (or other data) on the screen when the camera’s shutter is closed. Cranes can also be fitted with encoders to relay position data. Completely markerless systems provide convenience, though they might struggle in a particularly featureless corner. With or without tracking, genlocking the display and camera might still involve a cable even now – it took the world a long time to work out wireless genlock. For more than one camera, sequential exposure systems are an option, but since these displays rely on pulse-width control, adding more cameras reduces the pulses per frame, ultimately leading to compromises in brightness control. Lenses may also need encoding for focus, iris and zoom. Some lenses have this built in (with at least two existing systems), while various bolt-on solutions are available.
scenes against a background image, but whatever we call it, ICVFX benefits the director, the actors and the people who no longer have to draw around Zoe Saldaña’s nose several thousand times. Don’t laugh – Dan Shor, who played the character Ram in TRON, reports having been accosted on the street by someone who had spent many months doing the same for him. The thing is, all those benefits have long been a hallmark of back projection, a technique that first earned Oscars in – wait for it – 1930. In fact, there are back-projected scenes in Aliens that still withstand modern scrutiny. Now, Cameron’s classic may be a touchstone of the real-world, practical-effects filmmaking that audiences value, but comparing it to modern VP might seem just a bit far-fetched. Today’s set-ups might involve camera tracking, real-time rendering of custom-built virtual worlds, 5000 DMX channels of image-based lighting and a dozen other refinements that certainly didn’t exist in 1985. What matters, perhaps, is that many of those technologies are also omitted from set-ups of today, and that’s okay. A full-capability VP stage involves a lot of complexity. The video wall is a multi-ton, multimillion-pound piece of hardware comprising display panels, receiver cards, processors and a small town’s worth of power and data cables. Equipment choices influence brightness, colour, frame rate and resolution, which in turn influence how closely it can
CHARIOTS OF FIRE Dimension brings ancient Rome back to life in Those About to Die
A s new ideas evolve into producers out in a nasty rash. Virtual production has been around for long enough to enter that phase, and it is certainly saving people both time and money. Whether it has become any easier, though, depends on what virtual means to any particular production. If that sounds like a redundant question, bear in mind that live broadcast often treats terms like virtual production and virtual studio as interchangeable. If we’re broadcasting the Olympics and ask the presenters not to wear green, that’s fine. However, for single-camera drama, especially when shooting something like Guardians of the Galaxy, with characters who are both blue and green (and pink, yellow, white and furry) all in the same frame, it becomes much more complex. In-camera VFX has become a catch- all term for photographing live-action established practices, they often become simpler, more affordable and less likely to bring cautious
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