'Game of Thrones' Showrunners Reveal Secrets Behind Ambitious Visual Effects, Final Season's Big Battle

This spring, winter is coming one last time as HBO's Game of Thrones reaches its conclusion. Creators David Benioff and Dan Weiss will unfurl the final season of their record-breaking epic beginning April 14, bringing finality to the stories of Jon Snow (Kit Harington), Daenerys Targaryen (Emilia Clarke) and all the other heroes and villains who have fought alongside them since the drama's 2011 debut.

Much has changed since Thrones first arrived on the scene, certainly within the context of the story. Dragons and White Walkers are no longer mere myths, as fire and ice descend upon the Seven Kingdoms in the final six episodes. Beyond the scope of the story, however, an equal amount of change has taken place, as Benioff and Weiss' tale has grown more complicated in the telling, requiring a global network of producers, crew members, actors and visual artists to bring Westeros to life.

Game of Thrones creators David Benioff and Dan Weiss, set to receive the Visual Effects Society Award for Creative Excellence at the 17th annual VES Awards on Feb. 5, took part in a joint interview over email with The Hollywood Reporter about the increasing scale of the show and how their perception of the VFX landscape has changed from the days when a final season was nothing more than a twinkle in their eye.

Game of Thrones is not only one of the most narratively complicated dramas on television but among the most visually arresting series as well. What was the earliest and most daunting visual effects challenge you faced as storytellers? Can you pinpoint a moment where you felt comfortable with the process?

The earliest challenge was learning to work in a VFX environment at all. As familiar as we all are with the end products, the VFX process is mysterious to people who haven't been directly involved in it. You can pick up bits and pieces flipping through Cinefex magazine and watching behind-the-scenes featurettes, but that only takes you so far. Learning to speak enough of the VFX language to communicate effectively with the native speakers was a process we began with Robert Stromberg, who supervised our original pilot. That process accelerated greatly when VFX producer Steve Kullback joined us in season two and brought us supervisor Joe Bauer in season three. Those two guys, along with the core members of the team like Adam Chazen, Chris Baird and others, have been and remain our primary VFX school teachers.

As far as comfort with the process goes, we love it precisely because we know we'll never get "comfortable" with it in the way you're comfortable with something you know inside and out. It's too deep a pool to ever reach the bottom, and the pool keeps getting deeper and wider every year as innovation continues to push the boundaries of what's possible. You're constantly learning, which is what keeps it fresh.

In the first season, the earliest challenges involved learning how to do a lot with a little. The show did not have tremendous resources to burn for VFX back then. We still remember the 4-hour-plus meetings where we'd go through the whole season, scene by scene, and count every set extension, every wire removal shot, look at every VFX blood hit to see if it could be done practically and save us a few hundred bucks. And then we'd do it all over again a few weeks later, so we could make the budget a number that was not going to grow. That was a very valuable experience, because it forced us to engage with the details of the process and not take the attitude, "Well, these VFX guys are very smart, they'll figure it out." Because no matter how much your resources increase, that way of thinking leads to a tremendous waste of time and money. Which in turn leads to things not looking and feeling the way they should.

What do you think fans would be most surprised to learn about the effort behind bringing Thrones to life, from a VFX standpoint?

As with any VFX-intensive project, the sheer amount and diversity of manpower would probably widen some eyes. It still does for us. And not just people working with computers, although there are many of those. Paul Hatchman, our key VFX grip, and his team have erected mammoth green screens, hundreds of feet long and over a hundred feet high, because they were necessary to shoot some of the larger-scale battle sequences. As the dragons have gotten larger, the process of tracking their movements for the actors and directors has gotten more complicated and recently moved over to simulcast technology, where pre-animated versions of the dragons are superimposed upon the actors and sets in real time. That way we can see what we're actually shooting while we're shooting it instead of having to figure out a way to shoehorn things together later. There's a lot of interaction with Sam Comway and his traditional special effects unit as well. Sam, Joe Bauer and company had to construct a motion-controlled flamethrower on a crane to shoot some of the dragons' fire-breathing shots. Watching that thing light 20 stuntmen at once on fire was a high point of the Game of Thrones experience.

And then there's the fact that, once the cuts are done and the shots go into the pipeline, they're being worked on by brilliant VFX teams all over the world: New Zealand, England, Canada, the U.S., Germany and many other places. It's truly a global effort. 

Looking back on the seven seasons released thus far, what stands out to you as the toughest scene in the show's history from a VFX standpoint?

There were a couple that were difficult. The ice lake sequence that Alan Taylor directed in season seven was one that incorporated a lot of different elements, each of which carries its own unique challenges: dragons, fire, extended and manipulated environments, VFX wights, active and action-driven crowd replication. Of course, [director Miguel Sapochnik's] "Battle of the Bastards" was also extremely difficult for similar reasons — not to mention horses and a giant. That one also needed to look as realistic as possible. The horses colliding with each other needed to look the same, even though one was real and another was CG. The armies needed to seem real, messy, and of a piece, even when three-quarters of the people in frame were either crowd replications or fully digital. Of course, the things we're doing for the final season go a good deal beyond either of those.

You mentioned the ice lake battle in "Beyond the Wall," which was followed by the season seven finale's destruction of the Wall — both of them visual marvels, and also monumental moments for the story.

They were very different sequences, inasmuch as the "Beyond the Wall" sequence involved so many in-camera elements: the ice lake itself, the set surrounding it, the wights, the White Walkers and Night King, the fire and such. In contrast, the balance of the fall of the Wall sequence tilted more heavily in favor of CG, since neither the dragon nor the Wall are really there. Both involved an extensive amount of [pre-visualization], which was developed, re-shot and re-cut many times. But in the case of the fall of the Wall, the previs landed a lot closer to the actual scene itself. For all the prep work that was done on the ice lake sequence, on the other hand, the actual sequence was built more traditionally in the editing room.

Filming on the final season is under your belt, with only a few months left until it arrives for fans across the world. What surprised you the most about the process of ending Game of Thrones, both on a practical level and an emotional one?

On a practical level, it was pretty intense. To make the agreed-upon date involved a tremendous amount of scheduling intelligence on the part of [producers] Bernie Caulfield and Chris Newman, and a tremendous amount of ingenuity from [visual effects producers] Steve Kullback and Joe Bauer — and Stefen Fangmeier and Jeff Schaper, whom Joe and Steve brought in to help supervise the large quantities of simultaneous VFX work that no one person could possibly supervise on his own.

We always knew this had to be a story that ended when it was time for it to end, and not one that got dragged out until it had worn out its welcome. We knew this moment was coming, but it's still impossible to prepare yourself fully for it. We're dealing with it piecemeal as we finish up the season. We're also in a tremendous amount of denial. Six months from now, you'll probably find us both wandering down Sunset Boulevard in our Game of Thrones crew jackets, wearing headphones, muttering notes to an assistant director who isn't there.

The final season is said to feature the biggest battle sequence ever featured on Thrones. How does it compare to "Battle of the Bastards," the current title holder?

In terms of sheer scope, there is a lot in this season that outstrips the "Battle of the Bastards" sequence so expertly directed by Miguel Sapochnik. We can say this without feeling bad, since most of it was also expertly directed by Miguel Sapochnik.

A version of this story first appeared in the Jan. 30 issue of The Hollywood Reporter magazine. To receive the magazine, click here to subscribe.