"People come here because they know it's their chance to do something really great and to get it up on the screen," he said in a recent interview.
Jackson, who declined to be interviewed for this story, launched Weta in 1993 with fellow filmmakers Jamie Selkirk and Richard Taylor. Named after an oversized New Zealand insect, the company later was split into its digital arm and Weta Workshop, which makes props and costumes.
Loving homages to the craft are present in Weta Digital's seven buildings around the green-hilled suburb of Miramar. There are old-time movie posters, prop skulls of dinosaurs and apes, and a wall of latex face impressions of actors from Chris O'Donnell to Tom Cruise.
Its huge data center, with the computing power of 30,000 laptops, resembles a milk-processing plant because only the dairy industry in New Zealand knew how to build cooling systems on such a grand scale.
Little of Weta's current work was visible. Visitors must sign confidentiality agreements, and the working areas of the facilities are off-limits. The company is secretive about any unannounced projects, beyond saying Weta will be working solidly for the next two years, when the two later "Hobbit" films are scheduled to be released.
The workforce has changed from majority American to about 60 percent New Zealanders. The only skill that's needed, Letteri says, is the ability to use a computer as a tool.
Beyond having creativity as a filmmaker, Jackson has proved a savvy businessman, Letteri says.
"The film business in general is volatile, and visual effects has to be sitting right on the crest of that wave," Letteri says. "We don't get asked to do something that somebody has seen before."
The government calculates that feature films contribute $560 million each year to New Zealand's economy. Like many countries, New Zealand offers incentives and rebates to film companies and will contribute about $100 million toward the $500 million production costs of "The Hobbit" trilogy. Almost every big budget film goes through Jackson's companies.