They certainly saved the best for last: The full-CG Hogwarts, the thrilling Gringotts break in and escape on a dragon, the Room of Requirements escapade with fire creatures, the battles, the ethereal encounter with Dumbledore and the final confrontation with Voldemort. Plus 3-D for the first time.
"Environments, especially, have been a breakthrough, asserts Tim Burke, the overall supervisor that has been on Potter since the second film, The Chamber of Secrets." It's all HDRI, and that way of photographing textures has given us incredibly detailed shots and the ability to relight things. It's all based on the proprietary tools to stitch this stuff together and make it work."
But the biggest decision was making Hogwarts CG for the first time. Double Negative and MPC split up the school and surrounding environments, and spent 18 months just on the design. "Basically, we were able to design and execute shots right up to final delivery," Burke adds. "It gave us a lot of flexibility. We were able to render things quickly without fussing around. It seems to me that we can turn around iterations so much quicker than ever before."
Since the ongoing war takes place at Hogwarts throughout the second-half of Part 2, it was essential that the battleground display sufficient detail and dynamic compositions, especially in light of the 3-D.
"David wanted to create these fantastic, big shots that link different parts of the action in different areas, going from outside the school to inside the school," Burke adds. "And all of the development that we've done and the extra high-resolution that we've corrected for have allowed us to fly around courtyards and into windows during critical moments of the battle, and has made the whole experience very visceral and given the camera a way of being immersive."
Double Neg (supervised by David Vickery) was the lead vendor and the equivalent of the miniature model facility, only in CG. They started building the school and surrounding environment at the end of 2008, led by Pietro Ponti, the environment supervisor. Their work includes the battle of Hogwarts and wooden bridge attack. They also did the first sequence, where Harry and his friends break into Gringotts bank, have the wild cart ride into the cavernous vault and then escape on the dragon. Burke particularly likes the forlorn look of this imprisoned creature, which distinguishes it from other dragons.
Tippett Studio, meanwhile, did the treasure inside the vault (supervised by Matt Jacobs). All treasure mass was created for each of the shots, thus all practical effects were removed. They ray-traced the volume of metallic surfaces and managing the choreography of the mass for each shot proved challenging.
MPC was the other major vendor (supervised by Greg Butler). "We drew a virtual line through the school at the end of the courtyard," Burke explains. "The new viaduct where the giants battle the stone knights was MPC's work along with the hillside that attaches to it where Voldemort arrives."
MPC also created the CG crowds with nearly 1,000 Death Eaters and CG close-ups of the giants and the stone knights, which were treated as pure animation because they had to be robotic in their movements. "We did lots of studies of performance and stripped out the humanistic characteristics and turned them into automatons," Burke continues.
This is where they got into crucial sharing of assets as a result of the 3-D conversion (supervised in-house by Hugh Murray of IMAX and involving several vendors, including Pixel Magic, Sassoon, Animal Logic and Prime Focus). But there were also 300 CG shots fully rendered in stereo by the VFX companies.
MPC additionally did the Room of Requirement sequence, which was much larger than the previous one because of the chase with CG fire creatures. "We built a large set and did a full-CG extension to that set and then switched to a full-CG set for flexibility with camera movements," Burke adds.
A chaotic river of fire was created using the Flowline simulation software licensed from Scanline . This combination of water and fire simulation also contained magical creatures that pursue Harry and his friends and try to trap them in the room.
Framestore did the King's Cross White Mist sequence when Harry encounters Dumbledore in the afterlife. :We texture shot the real King's Cross as the basis of the build and then crafted a white, ethereal environment and shot the actors on a white platform for them to walk up and down in and surrounded it with silks," Burke explains.
"You can see each year how the level of work progressed at each company and what their strengths were," Burke concludes. "There's plenty of continuing work with Hollywood: I just hope the London houses take advantage of the momentum and continue to improve, but don't over reach and blow it."
Bill Desowitz is former senior editor of AWN and editor of VFXWorld. He has a new blog, Immersed in Movies (www.billdesowitz.com ), and is currently writing a book about the evolution of James Bond from Connery to Craig, scheduled for publication next year, which is the 50th anniversary of the franchise.