In HBO's Game of Thrones (airing Sundays at 9:00 pm and concluding its first season June 19), environments are especially crucial to the VFX. In fact, there are four distinct worlds representing the different regions for this violent struggle for total power between seven medieval noble families. As a result, it's "The Sopranos set in Middle Earth," suggests David Benioff, who created the series with D.B. Weiss.

"The main challenge was to create or extend environments that would be totally believable and could have existed in a parallel medieval world," says Lucy Ainsworth-Taylor, the visual effects producer. "Therefore, although being fantasy, there was very little scope to be fantastical."

The lead vendor was London-based BlueBolt, which took on all the CG environments, CG creatures and matte paintings. Screen Scene in Dublin provided an in-house comp team and did a lot of shots involving CG swords & blades and crowd comps. Meanwhile, to meet the tight post schedule, they used a few vendors in LA: CHE, Outsource, Encore and Look FX.

Overall, Game of Thrones, which has been renewed, has around 700 shots (episode one required 180). Approximately half are fix its with easy comp, and the remainder are far more solid environmental CG shots along with some very creative comp to help the series along, according to visual effects supervisor Adam McInnes.

"The budget was tight for VFX, but not for television," Taylor continues. "It was ambitious from the start. We had to take an early call on the approach to certain shots, what was a 3D build, what was a 2D matte painting, etc. However, in advance, BlueBolt realized that if they did some simple builds on certain key environments which were only ever going to be matte paintings it would help further down the line. These simple builds allowed us to move the actual buildings around (Red Keep, The Twins) to get the layout working on the individual shots with the lighting working on the original plates. Our element shoot provided of lots of blood spurts, snow, breath, which became invaluable in post for all the VFX houses. Violence presented no problems; there appeared to be no limits to how graphic we could be in depicting the horror."

The series was shot predominantly in Northern Ireland. A lot of the interior sets were built at the Painthall, an incredibly tall warehouse on the docks of Belfast. This allowed for a large scale and height of set build. There was a nine-week shoot in Malta simultaneously, covered by VFX Supervisor Angela Barson. This is where all of the Kings Landing exteriors and The Dothraki wedding were shot. Castle Black was a large location build in a quarry just outside Belfast. The interior courtyard was practical to a certain height and required VFX top ups when they shot off the set to include either towers or, where visible, the CG ice wall.

The highlights have been the environments and the opening shot of the Wall when the riders come out on the North side. "The gate goes up and [the first shot] is a VFX composite using bluescreen footage of the rangers and the gate plus the second courtyard of Castle Black in the background," explains McInnes.

"When the rangers exit into the North we see for the first time some idea of the sheer scale of the Wall," he continues. "This was created by matte painting to extend a physically snowed up area around the live action. Our aim was to create something that had a hint of man-made structure about it and had to appear completely insurmountable or unscalable as it was built to defend from the creatures of the North. The edge of the forest was introduced using stills of snowy pines and atmospheric mist and snow composited in to create depth and movement.

Winterfell itself is essentially a digital matte painting using some 2.5D with the towers that they decided early in planning would provide maximum scope for reusing the assets with minimal cost implication for producing variations of similar angles.

"The Red Keep lent itself to a 3D build. We took concept work as a template and rebuilt it. In texturing we needed to create a transition from the yellower stone of Malta to the red stone from which the castle's title is derived. It had to be grand and beautiful, imply wealth and power, be extraordinary to the world as we know it but at the same time not veer too far into the fantastical."

Another significant feature of the series is the Eyrie. This is an impenetrable fortress high up on a rock base. "We went through a number of iterations of the concept on this being one of the most fantastical pieces of the series," McInnes says. "There were several options considered as to how the access should work in conjunction with the practicalities and location of shooting the arrival of Catelyn and her entourage. Ultimately, we opted for them rounding a bend on the edge of a gorge where we see the Eyrie perched in the distance only accessible via a guarded rock arch bridge."

Game of Thrones is one of the earliest productions shot digitally with the Arri Alexa cameras. The VFX team was involved in establishing a workflow from acquisition to delivery and received copies of LUTs to use as a guide when lighting and compositing and to deliver cutting copy versions of VFX that would look similar to dailies. Their delivery was still ungraded LogC DPX to the DI so that it would match original camera media and had maximum latitude when it came to developing the final look of the show. McInnes says they were blown away by the results of keying and grading.

Maya and Nuke were the standard software at BlueBolt. The matte painters used Photo Shop and Mari. Mud Box was used for some additional finessing of the models and all rendering was done using 3Delight.

Coming up, McInnes promises fantastic-looking dragons, which will hatched in the final episode of the season, "Fire and Blood." "The one area we really took great care on [was] the dragons in episode 10. We insisted on storyboards, previs and a maquette in order to get the builds underway in advance, knowing the limited post schedule coming up."

Bill Desowitz is senior editor of AWN & VFXWorld.