Cast The actresses Zoe Saldana (above) and Michelle Rodriguez (below), who play the Na’vi Neytiri and human pilot Trudy Chacon, respectively. Sam Worthington plays the film’s protagonist, Jake Sully, a paraplegic Marine becomes part of the Avatar project occupying the position as a scientist, exerted his recently deceased twin brother. After watching numerous candidates for the role in the United States, Margery Simkin, casting director of the film, James Cameron suggested that expanded the search to other English speaking countries like the United Kingdom, Ireland and Australia, was then Simkin when contacted with Christine King, a casting director in Australia with whom he had worked in the past, and asked him to select several candidates for the role.Among them was Sam Worthington, who despite being skeptical at first because of the secrecy surrounding the project and few details about the character of Jake, made a couple of tests before the cameras and eventually was chosen by some actors that the study had advocated for the role. Actor Stephen Lang, Colonel Quaritch interpreter in the International Convention San Diego Comics 2009. Zoe Saldana plays Neytiri, a native inhabitant of Pandora is forced to educate as Jake Sully Na’vi and who eventually ends up in love. Like all Na’vi was created using the method of motion capture and computer generated. Sigourney Weaver plays Dr. Grace Augustine, a botanist who in turn is a mentor to Jake Sully in the project Avatar. At first it was called Shipley, referring to Ellen Ripley, Weaver played the character in a film of James Cameron: Aliens (1986).The actress, who dyed red hair for the role, stated that Dr. Grace Augustine reminded James Cameron himself, being “very stubborn and idealistic.” Stephen Lang plays the Colonel Quaritch, military commander project and responsible for security of the base.Lang had auditioned for the role of Cameron in Aliens who did not get it, but reminded the actor and director chose him to Avatar. Michelle Rodriguez appears as Trudy Chacon, a helicopter pilot who has two years part of the military corps based in Pandora and ends up becoming a renegade Na’vi to help in the fight to preserve their lands. Cameron wanted to work with the actress after she saw it in the movie Girlfight ( 2000). Also included in the main cast actors Giovanni Ribisi, who plays Selfridge, a character from the passive-aggressive type who is in charge of the mission and make decisions under pressure from the military, Joel Moore in Norm role Spellman, an anthropologist who studies project Avatar plants, nature and life of Pandora, Matt Gerald as Corporal Lyle Wainfleet, and Laz Alonso as Tsu’tey, successor to the chief of the tribe.