WELLINGTON, NEW ZEALAND — The Balrog, the Ents, the Orc armies, the Oscars. All the hard lessons learned in Weta Digital’s effects work for Peter Jackson’s Lord of the Rings trilogy helped Weta deal with an 8,000-pound gorilla and other fantastic creatures that interact with (and kill) human characters in Jackson’s new King Kong remake. And there were new lessons, too.

Academy eyes will surely be trained this season on the seamless visual effects for Kong — especially given its dramatic portrayal of two craggy islands teeming with primitive life forms: Skull Island and Manhattan.

Much of Kong’s compositing work involves innovations Weta developed in-house after LOTR wrapped. “Our biggest compositing innovation on Kong was probably incorporating 3D tools directly into the mainstream of our compositing pipeline,” says Weta Digital FX supervisor Dan Lemmon. He says Weta uses a variety of off-the-shelf software, both third-party and proprietary plug-ins, and a few stand-alone programs written at Weta Digital. “We use Nuke from D2 Software as well as an Apple Shake plug-in called Cyco, developed at Weta by 3D sequence lead Nick McKenzie,” Lemmon says.

Weta Digital’s compositing supervisor Erik Winquist adds, “Just like on LOTR, our primary compositing pipeline revolved around Shake.” To help speed shots through the King Kong pipeline, Winquist says, “in-house genius” McKenzie wrote several custom plug-ins, “from a sequencer-like tool for animating the illuminated signage in Times Square, all the way up to a full-blown 3D interface and accompanying suite of tools inside of Shake to simplify the placement of elements on cards in the comp.”

Skull Island in ‘2.5D’

“One of the biggest challenges on this show was the amount of virtual locations that had to be brought to life in the composites,” says Winquist. “An enormous number of miniature elements were built and shot for the various Skull Island locations, but those were often the broad strokes: key pieces of architecture or terrain foreground elements would then be expanded via virtual jungles and matte paintings. Peter said from the beginning that he wanted Skull Island to have the look of glass matte paintings from the original 1933 film,” Winquist says, “dark silhouetted foregrounds with increasingly bright, layered atmospheric backgrounds. The main challenge became staying true to the spirit of those static compositions with the broad, sweeping, signature Peter Jackson camera moves that are everywhere in this film.”

Winquist adds, “For the dynamic action sequences where the camera traveled sizeable distances over the course of a shot, the Miniatures Units typically shot motion-control camera moves with multiple lighting and matte passes, which were integrated in the comp with matte paintings, CG elements and plate photography. This is pretty standard for us and was used all throughout the LOTR trilogy.”

Due to King Kong’s enormous workload it became clear that Weta’s Miniatures Units, and Oscar-winning miniatures DP Alex Funke, couldn't wait for animation to dictate the motion-control moves on every shot, Winquist says. “So wherever possible, the Miniatures Units would instead shoot a set of tiled passes of the miniature with a standardized nodal motion-control move in set intervals. These tile sets were then assembled in 2.5D at Weta Digital and used as virtual environments, freeing the animators to let the action dictate the camera moves instead of being locked into a plate.”

To accomplish this, Winquist says, “We adopted D2 Software's Nuke compositing software which is really fast and has a great set of scriptable tools for pan-and-tile 2.5D and 3D projection setups.”

To render such intricate virtual jungles in full 3D with all of the organic detail found in reality would be too time consuming for King Kong’s tight schedule, Winquist says. “So for the most part, the jungle extensions were created in the composite with a library of hundreds of separate miniature bluescreen trees created by Weta Workshop and shot high speed with wind to make sure every time we see jungle, it feels like a living place.”

With a suite of custom plug-ins for Shake, compositors were able to load the virtual camera for their shot and one by one, dress in photographed miniature trees on virtual cards in 3D space.

Little old New York

VFX supervisor Lemmon says one of the biggest compositing challenges in creating New York ca.1933 was developing a look for the city that would work for the whole end sequence — the final showdown which takes place at the top of the Empire State Building and involves a squadron of Navy biplanes attacking Kong from every direction. “The sequence opens during the twilight of early morning and ends not long after sunrise” Lemmon says, “so we had to account for dramatic changes in the lighting of the city and the sky as the sequence progressed.”

To re-create the look of vintage, antennae-free Manhattan, digital compositing supervisor Charlie Tait and 3D sequence lead Craig Wentworth created an elaborate city "pre-comp" that used nearly 50 CG layers to build about 10 primary city elements, says Lemmon.