One particular example where practical sets and CG backgrounds were integrated is a sequence that takes place as Arthur and his band of Sarmatian Knights arrive at the Roman Consul’s Estate. “A practical gateway was constructed on location, with a greenscreen behind the open door that leads into the villa. All the estate buildings, pathways and poplar trees were generated in the computer and composited into the scene.”

The goal of the effects wizards was to make the action look real.

A Virtual Climax
Johnson is as much a fan of past cinema as the films of the present. “I am a big fan of the work of David Lean and other makers of classic Hollywood epics. Their work was always in the back of my mind while working on the panoramic visual effects shots. I guess the main difference between what we do now and what they did in the fifties and sixties is that we have a resource available to us of a digital cast of thousands. They needed to costume and feed every actor in their epic crowd scenes.”

This new capacity to digitally create casts of thousands is shown to its best effect in the climactic battle of Arthur and the Woads against the entire Saxon Army. It is a testament to the quality of the effects and homogenizing effect of the digital intermediary that in the final battle there is not a single scene that looks artificial. “Cinesite wrote its own proprietary crowd simulation/artificial intelligence system called REACT,” Johnson points out. “We found using our own proprietary software allowed better integration of the tools within the workflow of the facility.”

Motion capture was used for animation cycles. “For the CG Saxon army basic walk, run and fighting, clips were recorded and integrated into REACT.”

Finishing Touches
Johnson rounds out describing his work by mentioning subtle effects that should not be overlooked simply because they blend seamlessly. “A CG hawk was created for the film, but was animated “traditionally” by our 3D team. A variety of techniques were used for the weapons. Several shots of Excalibur use an extended CG blade, and other scenes use CG arrows, both flaming and unlit. At other times throughout the movie swords, axes, crossbow bolts etc. have been animated and combined with the background footage. In one scene a digital scar was tracked onto the principal actor’s face. This effect was achieved by tracking and 3D warping 2D artwork using Inferno.”

Henry Turner is a writer and award-winning filmmaker, whose Lovecraft-inspired horror feature, Wilbur Whateley, won top awards at the Chicago International Film Festival. His writing on film has appeared in the Los Angeles Times, L’ecran Fantastique, Variety and many other publications. A longtime film festival executive, he has programmed for the Slamdance Film Festival, and currently heads FilmTraffick L.A.