The main architects of the that technology were Dennis Muren, visual-effects supervisor at Industrial Light and Magic Company, and Phil Tippett, a specialist in animal-movement animation.
The sky bison was rendered entirely in computer graphics for the film by Industrial Light & Magic (ILM), with Pablo Helman as visual-effects supervisor.
When the compositing session ends, Doug Smith, the visual-effects supervisor, mentions to Mr. Emmerich that the sound for this shot is finished.
"We can separate actors from background with a lot of precision," says Dennis Muren, the senior visual-effects supervisor at Industrial Light, "and then place the dinosaurs exactly where we want them."
Tsui also invited Chuck Comisky, the visual-effects supervisor for James Cameron's Avatar, as the 3-D director to manage the special effects.
"It was so important to get the audience back into the 1930's, which was necessary to the drama of the original story," said Joe Letteri, the film's senior visual-effects supervisor.
"A couple of years ago everybody's mouths were hanging open because 'Jurassic Park' had seven minutes of computer-generated effects," says Tricia Ashford, the film's digital visual-effects supervisor.
Craig Barron is an American visual-effects supervisor who specializes in seamless matte painting effects.
Jon Farhat, the visual-effects supervisor who gave Mr. Murphy a believable case of multiple personality disorder for that film, does an artful, unobtrusive job of integrating computer-generated animal acting with real creatures here.
He explained to the visual-effects supervisor what they wanted for this scene.