AniMation

WALL-E went undeveloped during the 1990s partly because Stanton and Pixar were not confident enough yet to have a feature length film with a main character that behaved like Luxo Jr. or R2-D2.[9] Stanton explained there are two types of robots in cinema: "human[s] with metal skin", like the Tin Man, or "machine[s] with function" like Luxo and R2. He found the latter idea "powerful" because it allowed the audience to project personalities onto the characters, as they do with babies and pets: "You're compelled ... you almost can't stop yourself from finishing the sentence 'Oh, I think it likes me! I think it's hungry! I think it wants to go for a walk!'"[36] He added, "We wanted the audience to believe they were witnessing a machine that has come to life."[5] The animators visited recycling stations to study machinery, and also met robot designers, visited NASA's Jet Propulsion Laboratory to study robots, watched a recording of a Mars rover,[16] and borrowed a bomb detecting robot from the San Francisco Police Department. Simplicity was preferred in their performances as giving them too many movements would make them feel human.[5]

Stanton wanted WALL-E to be a box and EVE to be like an egg.[37] WALL-E's eyes were inspired by a pair of binoculars Stanton was given when watching the Oakland Athletics play against the Boston Red Sox. He "missed the entire inning" because he was distracted by them.[38] The director was reminded of Buster Keaton and decided the robot would not need a nose or mouth.[39] Stanton added a zoom lens to make WALL-E more sympathetic.[39] Ralph Eggleston noted this feature gave the animators more to work with and gave the robot a child-like quality.[31] Pixar's studies of trash compactors during their visits to recycling stations inspired his body.[5] His tank treads were inspired by a wheelchair someone had developed that used treads instead of wheels.[37] The animators wanted him to have elbows, but realized this was unrealistic because he is only designed to pull garbage into his body.[5] His arms also looked very flimsy when they did a test of him waving.[37] Animation director Angus MacLane suggested they attach his arms to a track on the sides of his body to move them around, based on the inkjet printers his father designed. This arm design contributed to creating the character's posture, so if they wanted him to be nervous, they would lower them.[40] Stanton was unaware of the similarities between WALL-E and Johnny 5 from Short Circuit until others pointed it out to him.[9]

Auto, the captain and EVE

Stanton wanted EVE to be at the higher end of technology, and asked iPod designer Jonathan Ive to inspect her design. He was very impressed.[8] Her eyes are modelled on Lite-Brite toys,[39] but Pixar chose to not make them overly expressive as it would be too easy to have her eyes turn into hearts to express love or something similar.[37] Her limited design meant the animators had to treat her like a drawing, relying on posing her body to express emotion.[5] They also found her similar to a manatee or a narwhal because her floating body resembled an underwater creature.[37] Auto was a conscious homage to HAL 9000 from 2001: A Space Odyssey, and the usage of Also sprach Zarathustra for the showdown between the captain and Auto furthers that.[9][not in citation given] The manner in which he hangs from a wall gives him a threatening feel, like a spider.[41] Originally, Auto was designed entirely differently, resembling EVE, but masculine and authoritative; the Steward robots were also more aggressive Patrol-bots.[21] The majority of the robot cast were formed with the Build-a-bot program, where different heads, arms and treads were combined together in over a hundred variations.[5] The humans were modelled on sea lions due to their blubbery bodies,[31] as well as babies. The filmmakers noticed baby fat is a lot tighter than adult fat and copied that texture for the film's humans.[42]

To animate their robots, Pixar watched a Keaton and a Chaplin film every day for almost a year, and occasionally a Harold Lloyd picture.[9] Afterwards, the filmmakers knew all emotions could be conveyed silently. Stanton cited Keaton's "great stone face" as giving them perseverance in animating a character with an unchanging expression.[39] As he rewatched these, Stanton felt that filmmakers – since the advent of sound – relied on dialogue too much to convey exposition.[9] The filmmakers dubbed the cockroach WALL-E keeps as a pet "Hal", in reference to silent film producer Hal Roach (as well as being an additional reference to HAL 9000).[5] They also watched 2001: A Space Odyssey, The Black Stallion and Never Cry Wolf, films that had sound but were not reliant on dialogue.[34] Stanton acknowledged Silent Running as an influence because its silent robots were a forerunner to the likes of R2-D2,[25] and that the "hopeless romantic" Woody Allen also inspired WALL-E.[13]