Wednesday, May 28, 2008

Prince Caspian: A Darker and Grander Narnia
The Chronicles of Narnia: Prince Caspian offers more action and greater CG interaction with actors, so Alain Bielik speaks to Dean Wright and Wendy Rogers about the latest set of challenges.
By Alain Bielik

Nine vendors worked on Prince Caspian for a total shot count of 1,600. CG Aslan was created by Framestore. All images © Disney Enterprises Inc. and Walden Media LLC.
In 2005, the first installment of the Chronicles of Narnia franchise met an enthusiastic response from audiences worldwide. It also garnered an Academy Award nomination for best visual effects, rewarding the remarkable work achieved by Dean Wright (overall visual effects supervisor), Bill Westenhofer (Rhythm & Hues), Jim Berney (Sony Pictures Imageworks) and Scott Farrar (ILM).
Two-and-a-half years later, the Pevensie children are back in Narnia in Prince Caspian (which opened May 16 from Disney), and most of the first film's creative team returns, too, including Wright as overall vfx supervisor. This time though, he shared his supervisory position with Narnia newcomer Wendy Rogers, a former colleague of director Andrew Adamson at PDI. "The scope of this movie is so much grander," Wright observes. "It really is an epic leap, effects wise. We had a lot more CG characters and much more physical interaction with human characters. We also had a large amount of environment work, which was minimal in the first movie. It was so much work that I was glad Wendy joined us to co-supervise the effects."

With a vfx shot count of 1,600, Prince Caspian has only 100 shots more than The Lion, the Witch and the Wardrobe. Yet, the work turned out to be far more complex. "On the first movie, those 1,500 shots included 300 fix-its and miscellaneous effects," Wright notes. "So, we really had about 1,200 complex shots. On Prince Caspian, we had 1,600 very complicated shots! Ninety percent of them featured digital characters, sometimes hundreds of them…"

The film's major environment, Miraz Castle, was built as a miniature and was featured in more than 300 shots. Here, Edmund is about to embark on a night raid.

A New Narnia Made in London
Although Wright and his production colleagues were very satisfied with the work accomplished by the U.S.-based vendors on the original movie, they decided to turn to London-based companies for the sequel. "The first movie was shot in New Zealand and post-produced in L.A.," Wright recalls, "which made American vfx vendors a logical choice. This time, though, we shot in Prague, Czech Republic, and post-production took place in London. It made sense that all the key visual effects were created there too. It was also a question of resources: who had the capacity to produce so many shots in the time that we had? In the last show, the lead vendor did about 400 shots. This time, it was more than twice as much!"
Nine vendors worked on Prince Caspian, some of them working on shared shots, which explains why the total shot count of 1,600 isn't a sum of the individual shots.
• MPC -- 842 shots
CG Reepicheep, full CG Narnians, CG Narnian/actor hybrids (Centaurs, Fauns, Satyrs and all other CG creatures except those noted below) for all sequences (castle raid, final battle sequence, including CG trees attack, Council sequences, etc.), Telmarine army extensions
• Framestore CFC -- 514 shots
CG Trufflehunter, CG Aslan, CG squirrel Pattertwig, Dryad Dream, Tube Station transition, Magic Door (CG tree), set extensions (Buruna bridge sequences, including CG soldiers, trebuchets, etc.); Cair Paravel, etc.
• Weta Digital -- 296 shots
CG Bear, CG Werewolf, CG Ice and CG White Witch enhancements (hair and dress extensions); plus all Miraz Castle environment work, including miniature comps, CG set extensions, fully CG environments, 2D & 3D matte paintings
• ScanlineVFX -- 22 shots
CG River God
• Studio C --34 shots
CG breath and CG Hag eye enhancement
• Rising Sun, Cinesite, Rainmaker, production unit --141 shots
Additional vfx work

The filmmakers always had an onset human performer as a shooting reference. An actor dressed in a blue or green suit played the Werewolf (above), the Bear and Aslan, which gave the other actors something tangible to react to.

The Mother of all Miniatures
A critical decision was taken early on to create the film's major environment -- Miraz Castle -- as a miniature. A key location in the storyline, it was featured in more than 300 shots. "In the first movie, we had created the castle for the end sequence digitally, but it was a handful of shots," Wright remarks. "Miraz Castle played a central part in Prince Caspian. We already had a huge workload in terms of digital characters. By creating the castle as a miniature, we saved our digital resources for elements that couldn't be created any other way."
The castle was built at Richard Taylor's Weta Workshop, New Zealand, where most of the Lord of the Rings and King Kong worlds had been created. At 1/24-scale, it ended up being the largest single piece ever constructed by the studio. It was so large that the team had to tilt it at 30° for the camera to be able to capture aerial shots on stage. Another version was built at 1/100-scale and included the whole environment with a nearby village and background landscape. Weta Workshop also constructed separated miniatures of the village and the castle courtyard. The plates were later enhanced by sister company Weta Digital, under the watchful eye of VFX Supervisor Guy Williams, and combined with live-action shots of the actors on partial castle sets. "I feel that you always get better results when you have real elements in a shot," Wright adds. "They grab the viewer's attention and help sell the CG portions of the image. It was one of the advantages of having a real miniature that we could shoot, light and check in the viewfinder. We were able to get really tight on the walls and the surfaces would hold perfectly. We used the same approach for our crowd scenes: we always had a group of real extras in the foreground, and our CG army in the background. We tried to keep it all as real as possible."
Trying New Approaches
Having learned from the experience of shooting the first movie, Wright took new approaches to capture the visual effects plates featuring CG creatures. The first thing was to discard on set motion capture. On The Lion, the Witch and the Wardrobe, the technique proved very useful for Faun Tumnus, but not for the crowd scenes. The vendors ended up not using a lot of that data. "We decided to go for a more 'guerilla' approach on Prince Caspian," Wright notes. "We used three HD 24 fps 'witness' cameras to help capture the actors' performance. We would move them around the performers in order to triangulate their position in 3D space. Basically, it's the same technique that ILM used on Pirates of the Caribbean 2 and 3: you capture the live performance from varying angles, and then use that footage as a template to animate the corresponding CG character. It allowed us to add CG legs to the two-legged creatures, or a CG horse body to the Centaurs.
"Just like on the first movie, the performers were wearing blue pants or green pants, depending on if it was a day or night scene. The second thing that we did on set was to always have a human performer in the frame as a shooting reference. Most of the time, it was actor Shane Rangi in a big blue or green suit. He would play the Bear, the Werewolf, Aslan… His presence on set allowed the other actors to have something tangible to react to."
Building Creatures and Crowds
When the first movie had wrapped, Wright had gathered all the CG assets from the various vendors. Eventually, due to pipeline issues, most of the creature rigs had to be rebuilt from scratch by the new vendors. Textures were extensively upgraded too. That was the case at MPC, where the team led by VFX Supervisor Greg Butler was responsible for the creation of a huge menagerie: gryphons, big cats, wolves, bears, centaurs, minotaurs, etc. Some were full CG creations, others were a combination of live-action and CG body extensions. All required the development of complex fur or feathers. While working on 10,000 BC, MPC had developed a brand new grooming and lighting package called Furtility. The tool proved perfect for the array of creatures that had to be created for Prince Caspian. It allowed artists to vary the fur's look, texture and behavior creature by creature.

MPC used Furtility to create the new character Reepicheep, a swashbuckling mouse-chief.

The team was also responsible for creating a key new character, swashbuckling mouse-chief Reepicheep. The rodent was entirely designed by MPC's art department, and later voiced by Eddie Izzard. Captured on video, the comedian's performance provided a great reference for the animators in charge of bringing Reepicheep to life. Once again, Furtility enabled the team to create a detailed and believable fur. "Reepicheep is one of those characters that turns out to be quite difficult to nail down in animation," Rogers observes. "The question was: how much do you want to anthropomorphize him? How much can you open his shoulders before he loses his mouse-like quality? We also had to determine how he went from quadruped to biped position and reverse. Luckily, Andrew Adamson was very articulate in what he wanted. He would act out a whole scene in front of the animators, and very precisely show them the kind of emotion a character had to convey. Andrew was really instrumental in bringing these characters to life from an artistic perspective."
The final battle sequence proved to be quite a challenge for MPC. "We had about 5,000 Telmarines (human warriors) facing off 1,000 Narnia creatures of all kinds," Rogers adds. "For both armies, we had extras in the foreground in just about every shot. Then, MPC populated the background using their procedural crow system ALICE. The characters were animated using motion capture data augmented with key-frame animation when needed. Interestingly enough, the trickiest shots were not the real battle shots, but the ones in which the armies were standing still. It turned out to be real difficult to create a natural animation for characters that were just standing there. You have to find the right balance between motion and stillness."
For the centaurs, a variety of techniques were used, depending on the action that was required and the framing of the shot. A centaur could be a human performer with a CG horse body extension, or a real horse with a CG human torso extension, or a fully CG character.

MPC was responsible for the creation of a huge menagerie, including Asterius, the minotaur. Some creatures were full CG creations, others were a combination of live-action and CG body extensions.

The Return of Aslan
Meanwhile, at Framestore, VFX Supervisor Jon Thum and his team were busy tackling their own set of creatures, including the star of them all, Aslan. Voiced by Liam Neeson, the majestic god-like lion had been created -- successfully -- by Rhythm & Hues in the first movie. For the second movie, the team set out to make it look even better. Having recently created polar bears for The Golden Compass, Framestore had the perfect set of grooming tools to develop Aslan's mane. After months of development, the character was able to sport the most complex fur groom ever created at the studio.
Aslan's animation proved to be just as challenging, as the character's position in Narnia led to a specific behavior. "We tried not to over-animate him," Rogers observes. "He didn't need to move a lot to express his power, and we had to convey that by producing a subtle, even subdued performance, which is always difficult for animators. We spent a lot of time working on muscle structures and wrinkle placement to display emotions ideally. In one scene, Aslan is in full close-up and listens to what Lucy is telling him. The animators had to convey all his thoughts with minimal dialogue."
One of the aspects of Aslan that the team really wanted to improve on was his physicality. "We worked really hard to make him look and feel real," Wright says. "There is a scene in which young Lucy Pevensie hugs him and they both roll around playfully. We had to create a realistic interaction between Lucy's arms and Aslan's mane, which required a tremendous amount of work. First, we shot the plate with actress Georgie Henley hugging Shane Rangi wearing a fake Aslan head and torso -- we always filmed our 'stuffie' (KNB created a fantastic Aslan head with fake fur) as a lighting reference for every Aslan shot. Then, Framestore painstakingly removed Shane from the shots, and replaced him with the digital Aslan. A CG Lucy double was then animated to match the arms and head movements of the real actress. They were used as dynamics objects to generate realistic collisions with the CG mane, but the final composites feature the real arms and head. It was painstaking and complex work, but it really helped the character feel physically present in the scene."
Besides Aslan, Framestore also handled another key character, Trufflehunter. Since the badger is a newcomer in the Narnia saga, the team had to design and build it from scratch. Trufflehunter is considered by Narnians as the voice of wisdom, a character who remembers the old ways of their world. He had to deliver a lot of dialogue, but also feature typical badger behavior, notably when sniffing the air around him. Just like MPC with Reepicheep, Framestore's animation team worked hard to develop an animation style that would convey the character's acumen, while retaining his animal quality.

Framestore handled another key character, Trufflehunter, a newcomer in the Narnia saga. The animation team worked hard to develop an animation style that would convey the character's acumen, while retaining his animal quality.

Animating a Fluid Simulation
One of Prince Caspian's toughest animated technical challenges was tackled by ScanlineVFX, a German company (with a new L.A.-based office) that had recently garnered a lot of attention in the industry with its groundbreaking fluid simulation engine Flowline. "They had to create the River God, a giant character that is made out of the water of a river," Rogers says. "It constantly sucks water in a vortex motion from the river, spiraling up inside the body and pouring down again as his arms and hair. The character appears in only 22 shots, but they were all extremely complicated, as the team had to combine character animation and fluid simulation. And there's only so much that you can do to control a natural phenomenon before it no longer looks natural at all…"
To bring the River God to life, Scanline and VFX Supervisor Stephan Trojansky developed a system that allowed the artists to create directable fluid simulations within Flowline. It had to be a closed system where no single drop of water would disappear or could be cheated away.
The team developed a pipeline that based all simulation setups on a keyframe animatable polygon-character rig. Flowline was extended with features that allowed a realistic flow of the water with foam, splashes and bubbles, while following the keyframed motion of the character. One of the core features of Flowline is to allow rendering of all its simulation data in one beauty pass, including water, spray, bubbles, foam, self shadowing, global illumination and caustics. Indeed, the River God was created with just one beauty pass and some adjustment layers for the compositors to fine-tune the shots.
With all of its unique challenges, Rogers and Wright believe that Prince Caspian's visual effects succeed in surpassing the accomplishments of the first movie. "The second movie is definitely bigger, and I'm really proud with the work that was done," Wright concludes. "Most of the time, the vendors have actually exceeded our expectations. With Andrew's inspirational directions, they all did a fantastic job."
Alain Bielik is the founder and editor of renowned effects magazine S.F.X, published in France since 1991. He also contributes to various French publications, both print and online, and occasionally to Cinefex. In 2004, he organized a major special effects exhibition at the Musée International de la Miniature in Lyon, France.

Tuesday, May 06, 2008

Wolverine & The X-men (Trailer)