in planning for 3D; Stanton also believed that would be too much to deal with while shooting in any event. Mindel said that was "a huge relief". Work on the visual effects had begun even earlier, in 2009, before the release of Avatar, which revolutionized the field. The effects team doing proof-of-process tests realized when that movie came out that John Carter would require extensive use of all the techniques that Avatar had pioneered, and would go where that film had not with many more interactions between human actors and CGI characters. Peter Chiang, the film's visual effects supervisor at Double Negative in London, wrote a production bible for the latter that described how each character should be composed and framed. Bruce McCleery, the second unit's director of photography, said that bible was especially useful for scenes blending humans and CGI characters. "Working that out was much more complex than it sounds." Shooting the airship battle on a London soundstage required extensive preproduction work. Mindel and the lighting crew started work designing the lighting rig for that scene long before shooting started. They shared their work with the effects teams, which used Lidar to map it, as it did for every set. The sets housed the full airship models, mounted on gimbals with green screen on all sides. Ultimately, to stage an aerial battle with light-based weapons where the ships maneuver to block the sunlight that powers their opponents' craft, the lighting crew used 120 Spacelights, 15 Dino light banks, flashing lights and a crane mounted with soft lights and green screens that could fill in ambient light from the film's sky. Once production moved to the Utah desert, the weather added its own challenges. Heavy winds brought frequent sandstorms, forcing many on location to work while wearing goggles and sometimes burnooses. Mindel wanted the film to take advantage of these conditions as much as possible, although he had to tone it down slightly so the effects teams could do their job. "All the uncontrollable natural phenomena did give the film a visceral, unpredictable quality, and contributed to its unique, idiosyncratic texture," McCleery said. Reshoots Before the formal reshoot, which took place throughout September in the Los Angeles neighborhood of Playa Vista, Stanton told The New Yorker he had done some smaller-scale reshooting focusing on additional dialogue for some characters in order to address the issues the preview had raised.