Press release from Pixomondo:
Los Angeles, CA -- International visual effects company Pixomondo  is the primary VFX provider for the second season of HBO's award-winning fantasy television series Game of Thrones  created by David Benioff and D.B. Weiss. Season two features ten, one-hour episodes and premiered on April 1, 2012. Under the guidance of show VFX supervisor, Pixomondo's Rainer Gombos, and Pixomondo visual effects supervisor Juri Stanossek, the ambitious project is led by the company's Stuttgart facility, one of 12 Pixomondo studios around the world.
After the filming in Belfast, Croatia and Iceland for about 150 shooting days was complete, plates were turned over to Pixomondo. Though episodes were tackled primarily in order, Pixomondo began prepping the more difficult, VFX-heavy shots long before plates were received. On set, Gombos used storyboards and had an on-site previs team as well as a production designer so the shots were fully visualized before the cameras started rolling. Many of these complicated shots involved dragons, which were first revealed in the season one finale.
"The dragons mature this season so their look is more fierce," Gombos explained. "In the first season, the dragons are freshly hatched so they are more delicate. We changed the proportions up a bit and made the spikes more prominent so the dragons are much more menacing now."
Pixomondo's renowned creature specialist, Dan Katcher, who works out of the company's Burbank office and designed many of the dinosaurs in "Terra Nova," helped to model the new dragons. The Pixomondo team in Frankfurt tweaked the designs further and provided the animation to realistically bring the dragons to life.
In addition to creating the dragons, Pixomondo also did a substantial amount of set extensions, battle augmentation and some additional creature work. The on-set production designer helped develop the look of the sweeping shots. Then Pixomondo was tasked with capturing the essence of Westeros, the fictional continent in which the series takes place.
For the first season of "Game of Thrones," dogs were substituted for the direwolves, an unusually large and intelligent species of wolf in Westeros. In the second season, actual wolves were used. Using a variety of filming tricks and techniques, the shots were augmented to make the wolves appear larger and then composited with the background and actor passes for the final shots.
"The entire process of filming the wolves was quite complicated and required a great amount of precision, but the final shots with the supersized wolves really deliver the right impact," said Gombos.
Nine of Pixomondo's twelve facilities contributed to the project. Stuttgart served as the lead and did most of the set extension work and matte paintings as well as creature work and some CG gore. Frankfurt created the dragons and Berlin worked on shots featuring fluid simulations. London and Burbank handled compositing and 3D work though Beijing composited the shots with the direwolves and was also responsible for some of the long establishing shots as well as crowd replication and matte paintings. Munich, Hamburg and Shanghai assisted with compositing, with Shanghai also contributing to 3D shots.
Episode turnaround time has varied greatly depending on the complexity of the work. Unlike many shows, principal photography was mostly complete when the plates were turned over to Pixomondo in December 2011. Delivery of episodes has ranged anywhere from six weeks to four months and episodes feature anywhere from 60 to over 140 VFX shots.
In addition to Pixomondo, Gombos enlisted two outside vendors, Baked FX and Entity FX, to work on about 250 shots. The companies handled mostly paint fixes and cleanup, as well as some rain and snow augmentation.