Avatar hidden details: the dreams, languages and tech behind James Cameron's 2009 film

Avatar hidden details: Pandora began in two dreams

Cameron's own dream featured a glowing forest with fibre-optic trees, fan lizards and purple moss that lit up when stepped on, all of which made it into Pandora. Long before Avatar, his mother told him about a dream of a blue-skinned woman 12 feet tall. Cameron used that image in an unproduced screenplay he wrote in the 1970s and returned to those paintings when designing the Na'vi. He has also said making them blue connects them to Hindu deities.

A real language and a Na'vi music culture

Linguist Paul Frommer of USC created the Na'vi language, with a lexicon of about 1,000 words, around 30 contributed by Cameron. Its sounds include ejective consonants similar to those in Amharic. Composer James Horner worked with ethnomusicologist Wanda Bryant to build a musical culture for the Na'vi and recorded parts of the score with a chorus singing in Na'vi.

Cameron said he learned the word avatar from the cyberpunk novels Neuromancer by William Gibson and Islands in the Net by Bruce Sterling.

Nods to Aliens and other Easter eggs

Several details point back to Cameron's other films.

• Sigourney Weaver, star of Aliens, plays Grace, and the film opens with a military landing that echoes the earlier film, except here humans are the invaders.
• Cameron first named the character Grace Shipley, then changed it after casting Weaver because it sounded too close to Ripley.
• In the extended cut, a copy of Dr. Seuss's The Lorax, a story about protecting a forest, sits on a table in the Na'vi school scene.
• Sam Worthington briefly appears as Jake's dead identical twin, Tommy, whose place Jake takes.

How Sam Worthington got the part

Chris Evans, Chris Pine, Chris Pratt and Channing Tatum were considered for Jake, and Fox pushed for Jake Gyllenhaal. Worthington, then little known, grew frustrated after secretive auditions where he was not told what the film was or who was directing. His angry outburst caught Cameron's attention because he wanted an actor with grit. Cameron compared how Evans, Tatum and Worthington read Jake's rallying speech to the Na'vi and chose Worthington. Zoe Saldaña, cast early, helped screen-test actors for Jake, including Worthington.

The technology that waited for Avatar

Cameron put the film on hold until characters like Gollum, King Kong and Davy Jones convinced him the tech was ready. Production used a motion-capture stage six times larger than any before, with actors wearing skull caps fitted with tiny cameras to record facial expressions. Weta Digital, which at one point had 900 people on the film, rendered it on a server farm of 4,000 Hewlett-Packard servers, and the project needed over a petabyte of storage. Microsoft built a custom asset management system for the production called Gaia. Cameron credited the film's idea of a planetary world mind to Stanisław Lem's novel Solaris.

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