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April 2014
Issue: February 1, 2004

MOVING POST INTO PRE-VIZ

Visual effects supervisors and directors face a constant challenge: the desire to achieve the most dazzling visual effects possible (which amounts to almost anything in the digital realm) while staying in sync with budget realities and unyielding completion dates. Today, thanks to more powerful laptop computers and software, visual effects professionals can make smarter tradeoffs, thereby achieving the best possible effects within the given limitations.

Marc Leidy, a visual effects director who worked with Stargate Digital on the 2002-2003 season of CSI:Miami, lives by the maxim, "Don't leave for post what you can get done in prep." On location, he uses a portable visual effects studio comprised of a tiny DV camera, a Canon digital still camera, and a laptop loaded with Adobe After Effects and Photoshop to get the most out of limited pre- and post-production time.

Portable Visual Effects

Leidy uses his portable studio as a visual effects sketchbook in preproduction to quickly develop a specific look and flavor for producer approval before committing time-consuming post resources to the final result. "A few years ago, on-location compositing and pre-visualization wasn't really possible, but now laptops and off-the-shelf, affordable solutions have all the power and flexibility you need," says Leidy.

From a visual effects production standpoint, Leidy's challenge on CSI:Miami was to minimize costly and time-consuming revisions three or four days before air yet maximize the opportunities for the show's producers to offer their constructive input in the development of the shot. While some high-end productions can afford to hire an entire dedicated team for this process, this is a luxury beyond the reach of most film and TV projects.

Using affordable technologies, Leidy believes it is now more plausible than ever to move much of the post production process into pre-vis. "The process used to be: shoot first based on the script, then figure everything out later in post production," he says. "But now, schedules and budgets are so tight that concepts need to be tested long before the post production phase."

The approach of waiting until post production to consider how visual effects will actually be created not only involves a lot of trial and error, but also means that visual effects supervisors are sometimes less apt to take risks that might make a shot more realistic or impressive.

Moving post into pre-vis

Leidy uses a new kind of methodology. By taking his portable studio on location, he can develop an animatic on-site that is used to guide the shoot and will also later be used for the actual post production edit.

A typical case in point was for CSI:Miami episode "Spring Break." Leidy set up at the beach location where the opening scene was being filmed, a scene in which two passersby find a body lying in the sand. The gag called for the victim's head to flop over in a grizzly, unnatural manner, as if the neck had been broken.

Using Photoshop and a digital still camera, he quickly assembled a composite of suggested angles that took into account the actual location, the needs of the story, and production considerations. On the spot, everybody on the main unit crew saw the concept and was able to react quickly and efficiently. In this case this was particularly valuable, since there was only time to get one take before the sun went down.

"This is a good example of an effects shot that would have worked eventually, but probably not as successfully and cleanly because we might not have had the proper camera angles," says Leidy. "By doing a quick composite, we can accelerate the process and perhaps even take advantage of better opportunities."

Quick Experimentation

Leidy regularly used After Effects on the visual effects stage shoots as a compositing tool to check lineups and timings of motion-control shots. Because of the tight integration of Photoshop and After Effects, he can easily bring in Photoshop artwork developed by a matte painting department or his own 3D pre-vis and combine it in After Effects with the captured feed from the video tap of the effects camera, right on location.

This gives him the freedom to experiment with a number of ideas, quickly - without worrying about spending hundreds of dollars per hour in a high-end editing bay, or worse, realizing something isn't working that would require a re-shoot.

Effective, low-cost gear

From an equipment standpoint, Leidy believes everything you need can be assembled from a number of affordable, off-the-shelf tools. In addition to his mainstay tools, Adobe After Effects, Photoshop, and Maxon Cinema 4D, Leidy experiments with software like Realviz Stitcher - available for both Mac and PC - to build panoramas of virtual environments. He's also been known to use the software that comes with his Canon digital camera for simpler, cylindrical panoramas.

Leidy also uses shareware that allows him to create quick video overlays on location. His favorite video overlay tool for the Mac is BTV Pro software. For the PC, Leidy recommends Adobe Premiere Pro.

For video capture, Leidy likes the echoFX XLR8 InterView USB capture device for the Mac and Belkin USB VideoBus II for his PC laptop - neither requires a costly third-party video card, a major benefit.

From a hardware standpoint, Leidy recommends a PowerBook G4 Macintosh with at least a 1.25 GHz processor. On the PC side, he recommends a machine with a 1.7 GHz processor. For either platform, nothing less than a 15-inch screen and a 60 to 80 GB internal hard drive will do.

"Audience expectations of realism and believability are more precise than ever these days," says Leidy. "With a few off-the-shelf tools and a new way of looking at pre-visualization, productions can ‘wow' audiences while at the same time meeting budgets and deadlines."