Is Previs Finally Getting its Due?
Ron also emphasized that while they often work on pitchvis projects where the director comes to them with some fantastic idea and asks them to “just run with it,” they often work on things far more mundane but equally as important, that really help push forward the creative process of filmmaking. His teams strive to create something that captures the mood, the tone, the pacing and the emotional content of the final film. They’re also looking to achieve a great degree of accuracy. In all their work, they try to pay close attention to scale, distances, lenses, trying to keep the work as “real” as possible. “If you’re not showing the filmmaker something they can achieve, then there’s no reason to show them anything. It’s just going to lead to frustration and animosity within the production. The director, the producers, the studio will fall in love with it and suddenly it will fall onto the shoulders of the DP and the crew. They’ll look at it and say, ‘There’s no way to shoot this. It’s just not possible.’”
He showed an interesting previs clip from The Amazing Spider-Man, of the iconic scene where Spider-Man, from a first person POV, scrambles from rooftop to rooftop, flying through the air, finally landing smack onto the side of a big skyscraper, revealing his costume in the mirrored window for the first time. Because the first person POV was difficult to watch in stereoscopic 3-D, previs was used to figure out how much of and what type of movement the audience could stomach.
His next clip showed how previs was used on a yet to be announced film to diagram a complex camera move for a scene. It involved multiple camera rigs, planned views to show where the camera rigs would be situated on the set, what parts of the practical set would have to be removed, what parts would be CG, specing out the rigs, the directions the cameras were pointed in, getting down to the nitty gritty of production. Most importantly, it was all done weeks before the set was ever built. As Ron described, all that work was possible because of successful collaborative dialogue between the art department, the vfx team, the camera department and the previs artists, discussing what could be done, what couldn’t be done and how much time was needed to get it done. They were even able to build a custom camera rig because they got the information they needed early enough in the production. The previs work helped so much, during the shoot, they had saved enough time that they were able to take an additional half dozen lighting passes they never thought they’d have time to do.
Ron concluded by discussing how postvis has taken off over the years. Same teams, same tools, but very different from previs. According to Ron, “You’re providing the director and the editor something to work with while they’re cutting the film together. More often than not, what they’re trying to cut simply isn’t there yet. The output becomes a fantastic template for the visual effects houses to use.” On Hunger Games, Ron’s team received a lot of assets from vfx houses, working with the actual rigs, which helped insure they were working with the proper scale and design.
As he showed postvis clips of the mutt chase and tracker jackers scenes, he described how the postvis enabled them to find out what the animals were capable of doing, how they would scale. For tracker jackers, a key issue was how small they should be. Initially, they started out as big as scorpions. As the scene was being built, as the dramatic tension was building, they would change the animation to fit each new version of the sequence, blocking out how the wasps came out of the nest, how they moved, to flow with the tension rising in the scene, the sense of chaos. The vfx artists could then focus on making them all look fantastic, rather than on the iterative visualization process of the design that they’re not always setup to handle.
Ron’s team also created multiple versions with various degrees of gore to help the filmmakers find the ratings sweet spot they were looking for. “Previs artists work fast, iterative, doing multiple passes with different options, trying to make things look as clean as possible, but not worried about the final versions of anything.”
Sheena Duggal spoke next, sharing her perspective as a vfx supervisor who takes previs and turns it into a finished film. She began by commenting, “When you create a pitchvis to sell a movie project to a studio, you’re not really concerned with, ‘How do we shoot that?’ As a visual effects supervisor, it’s my job to take the previs and figure out how we shoot it, how we collaborate with all the other people who are part of the filmmaking process.” For the chariot stadium entrance in The Hunger Games, one of her big challenges was to take previs done by Halon, built with the director’s vision to pitch the movie, done without the boundaries of the physical world, and make that work within a real physical set location.
She showed a fascinating set of clips starting with the original previs sequence, followed by Google Maps-looking images that she called “Techvis,” various shots of the set location, marked up to show placements of chariots, horses, actors and green screens. She also showed final shots from the film, juxtaposed with the original pitchvis, to explain where scale, blocking, distance, crowd placement, camera angles and chariot positioning were modified, sometimes slightly, during the actual shoot.
As she explained, techvis involves getting answers to all the questions regarding shooting the sequence, figuring out all the parameters they had to look at before they could actually shoot the scene. For the chariot stadium entrance scene, issues to consider included:
- How many horses do you need? There are only a certain number of hours a horse can run on asphalt per day. How many yards do they need to run?
- In previs, you’re not thinking about how fast the chariot is traveling. What is a safe speed for the horses and actors? Horses get spooked by reflections and noise. How close can you put a camera to a horse without spooking it?
- What size green screen do we need? How do we design a set, using the physical location we’ve chosen, to maximize the shots based on where and how large our green screens can be setup?
- How can we shoot during the day to get consistent lighting?
- How many rows of the crowd can we get with 400 extras? We only had 400 extras that could effectively be made up as each took an hour to get into costume. How do we shoot the sequence to show 12 chariots when because of budget we only have six chariots?
Visual effects supervisor Boyd Shermis, the final presenter, has been using previs for almost 20 years in one form or another. His portion of the presentation focused on the use of previs in filming native stereoscopic 3-D. He showed a clip from a yet unreleased movie, where he had to design an aerial shot above a cityscape where a helicopter swooped down to handoff the camera to a vehicle on the ground. They mapped out the city of Vancouver, figured out the exact path of the helicopter, figured out the optimal lenses, both in the air and on the ground, figured out where to handoff the air-based camera to the ground-based camera to finish the shot. The previs and integrated planning had to determine how fast the helicopter was traveling, how high off the ground, in what direction and where the ground-based camera had to be met to take the handoff.