ERAGON has many grand set pieces, but none as big as The Battle of Farthen Dûr, where Urgals and Galbatorix’s elite army attack the Varden stronghold. The battle marks the end of Eragon’s journey and the climax of the story.

As the battle opens, Eragon and Saphira are helping fight off the king’s invading troops – leading to an aerial battle between Eragon and Durza, with Eragon atop Saphira, and Durza riding an enormous beast conjured from the dead soldiers on the ground below. The ground battle, involving hundreds of extras and stunt people captured on film during principal photography, as well as the CG extensions added during post-production, provides a backdrop for the aerial conflict – all under a dramatic moonlit sky. As the massive conflict unfolds, Farthen Dûr becomes nothing less than a vast theater of destruction.

As described in the story, the Varden stronghold is constructed in the crater of an extinct volcano. Against the cliff face are the remnants of an eroded white marble city, stoic ruins of a time past, built into the volcano wall, stretching and twisting a mile high.

Under the supervision of production designer Wolf Kroeger, the filmmakers built one of the biggest practical sets in motion picture history. The set was too spectacular to erect on a soundstage, so the production, after conducting several scouting expeditions, found an abandoned rock quarry and crater at a volcano in Hungary, near the Austria border. "That location worked out very well," says Kroeger, since it’s written in the script that Farthen Dûr is in a volcanic area."

Before construction could begin on this massive set, the filmmakers had to build an access road to get to the top of the crater. It took 16 weeks of planning, building and landscaping to create the set from an empty quarry into a lived-in community.

Peter MacDonald, one of the industry’s top second unit directors and action specialists – he worked on two "Superman" films, two "Batman" pictures and four "Harry Potter" blockbusters – collaborated with Stefen Fangmeier to bring the epic battle to life. "We wanted to give the sequence an edgy, combat-like feel," notes MacDonald, a director in his own right.

To capture the action, MacDonald worked with 450 extras and stunt people, 10 hours each night – often during frigid conditions (it was winter) – for several weeks. The sequence involves Urgals (who are uncommonly tall) and elves; many of the "Urgal" extras were 6’6" or taller, with those playing elves 5’0" or less.

The decision to shoot at night presented challenges to director of photography Hugh Johnson. "The location was a vast area with terraces and it was very difficult to get any lights up there," says Johnson, whose department went to elaborate lengths to rig the volcanic crater’s vast and treacherous spaces – employing a team of Russian mountaineers to haul the equipment.

For this sequence, Kym Barrett designed non-traditional costumes, this time of "armor." "I thought of what armor would be like in this particular world," says Barrett. "In this scene, Eragon rides Saphira and fights the invading forces, and he couldn’t be lugging around 25 pounds of armor plating. I also didn’t want the characters to look like they were wearing big, clunky suits of armor. I wanted it to be more streamlined, so I used leather for the armor." Barrett called in noted London couture leather makers to manufacture the unique pieces.

The completion of the second unit work in Hungary marked only the first step in the scene’s creation. Fangmeier, MacDonald and crew then moved to Pinewood Studios in England, where they shot blue screen work of Ed Speleers "riding" Saphira, battling Robert Carlyle’s Durza who is astride his own flying Beast. The filmmakers wanted to push these flying scenes to get, as MacDonald says, "the most dynamic sensation possible. It’s a real roller-coaster ride."

The actors were placed on computer-controlled rigs on hydraulics, upon which saddles were mounted. All the dragon’s movements – flying, gliding, banks-and-turns – could be experienced by Ed Speleers as Eragon. "Ed was a natural," says MacDonald. "He loved flying, and really wanted to get things right." Before Speleers began work on the motion rig, the filmmakers screened for him the pre-visualization footage as a reference for his "flying" maneuvers.

"ERAGON is the first film to really show the experience of flying on a dragon," says Fangmeier. "It was a lot of fun to create the flying sequences. We were challenged to maintain a physical reality but also have an element of the fantastical. We wanted dragon riding to feel like being on a jet fighter – with lots of ‘Wow’ moments."

Many of these "wow" moments were realized by New Zealand-based visual effects house WETA Digital, whose many credits include the "Lord of the Rings" trilogy, "King Kong" and "I, Robot." For the climactic Battle of Farthen Dûr sequence, WETA worked on giving Saphira a more aggressive "performance." "She’s taking on a more mature air at this point; she’s come of age," says WETA visual effects supervisor George Murphy. "We gave Saphira an additional sense of command, presence and agility that would get her through the battle."

"We developed Saphira in a physical way," adds WETA visual effects supervisor Guy Williams. "We have lots of views of her wings that occur during the battle, which are different from those of other scenes." Williams and Murphy also made the dragon combat-ready, with an impressive suit of armor.

In creating the lighting environments for the battle sequence, Williams and Murphy’s goal, again, was to have audiences connect with Saphira, as they would with the film’s human characters. They devised a realistic yet striking look for shots of her soaring majestically through the night – or conducting "strafing runs" on the enemy forces. "If we had relied only on light that was available, we’d have ended up with a couple of highlights of Saphira from the moon and that’s about it," notes Murphy. "So we came up with a color palette and levels that render Saphira visible, while reinforcing the fact that this is happening at night."

Murphy and Williams also created the fearsome creature that Durza conjures up out of the essence of the dead troops below. The Beast battles Saphira in an epic airborne duel. As described in the script, the conjured creature is a methodical killing machine bereft of fear or remorse. It is an enormous, dark, broiling cloud of smoke and ash – the face of death itself.

"Durza’s Beast provides a sharp physical contrast to Saphira’s naturalistic look," says Williams. "The beast is a completely task-built creature – a flying mouth of teeth, oversized head and teeth, and no legs. If you combined a large tarantula with a bat, then added a bull’s head with vampire teeth, you’d have the Beast."

"The character’s design came quickly," adds Murphy, "but developing the technology to render it was a challenge due to the inherent difficulties in ‘choreographing’ smoke, and action amongst the smoke."

WETA created effects extensions for the practical Hungary sets for the battle. "We had to master the exact terrain of the practical set so that we could match into portions of the live-action footage," says Williams. "All our action biases more towards one side of the volcano, which is visually more interesting because we’re closer to the volcano walls and get an enhanced sense of Saphira’s flying speed."

WETA worked on another big action sequence that combines spectacle with emotion, further exploring the connection between Eragon and Saphira, and a moving act of personal sacrifice. "We get to explore Saphira’s softer, gentler side in this scene," says Williams. "We pushed and refined her facial animation, keeping her movements very subtle, and letting the moments work for themselves."

In a magical moment that propels the character and story forward, WETA created a sequence in which Saphira undergoes a metamorphosis from adolescence to adulthood.

The visual effects from WETA and ILM, along with the exotic and rugged locations in Hungary and Slovakia, created the illusion of Alagaësia. ERAGON was one of the biggest productions ever to be filmed in Hungary and Slovakia.

The production crew of over-500 was headquartered in the historic city of Budapest. The set for Garrow’s Farm, where Eragon lived with his Uncle Garrow and cousin Roran, was built on privately owned land in a valley at Budakesi, a forty-five minute drive from Budapest.

The production constructed Galbatorix’s lair in a hillside cave, with access available only through a hole in the cave’s roof. Special cranes were used to move equipment – including cameras, sound recorders and set dressing – into the cave. Once inside the cave, the filmmakers’ activities were limited due to the area’s status as a national monument. Later, the mountains of Slovakia would provide a number of natural settings with spectacular views across valleys, gorges and waterfalls.

These worlds and characters created by these locations, effects artists, technicians, craftsmen, filmmakers and actors stem from the imagination of Christopher Paolini, whose novel is linked to the film in an unexpected way. "I originally conceived ERAGON as a movie," he points out. "I saw the characters and action clearly in my mind. But since I didn't have the money to produce a film, I ended up writing the story as a book."

At the time, it was beyond Paolini’s wildest dreams that a major studio would adapt his epic tale. But then, Paolini’s own life story, his imagination – and the journey of his heroic title character – remind us that no dream is too big.