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Realtime Demystifies Arthur’s Legend with ‘The Winter King’ VFX

VFX supervisor Sue Land discusses how the studio reimagined the legendary story, based on Bernard Cornwell’s ‘The Warlord Chronicles,’ aligning fantastical elements with plausible 6th century realism to visualize Sub-Roman Britain on the 10-episode MGM+ and ITVX fictionalized historical series.

At the heart of “The Warlord Chronicles” by author Bernard Cornwell lies a story that strips away the mystical elements to uncover the man, and events, that led Arthur Pendragon to become the legendary King Arthur. “The Winter King,” the first of the trilogy, has been adapted into a television series by One Big Picture, Bad Wolf, and Sony Pictures Television for ITVX and MGM+ under the leadership of Lachlan MacKinnon (Executive Producer), Catrin Lewis Defis (Producer) and Otto Bathurst (Director).  The 10 episodes were directed by Bathurst, Farren Blackburn and Anu Menon, who partnered with production designer James North and the visual effects company Realtime to recreate Sub-Roman Britain. 

While a grounded approach was taken, key characters and events of the Arthurian Legend still had to be respected.  “The way that Bernard Cornwell did his books was to utilize bits of the myth that have been added through quite a few centuries and put them back into the sixth century and our remit was to bring that to life,” explains Sue Land, Visual Effects Supervisor, Realtime.  “Our magic is something that somebody in the sixth century would think is magic.  For example, if I had a match and went back to the sixth century, I would be deemed as having a magic fire stick, but actually we all know it’s just a chemical reaction.  It could have been a bit of sleight of hand when Merlin brings the doves out of the Bull Head but there is still a way practically you could do that because there’s certainly space within it to have hidden them if he wanted to.”

Over half of the 802 visual effects shots contributed by Realtime centered around environments, with the main ones being Arthur’s stronghold Caer Cadarn, the opposing fort Caer Dolforwyn, and Avalon, where Merlin’s Tor is situated.  “We were the sole vendor, which gives you a different rapport with your client,” notes Land.  “It was collaborative with Bad Wolf and creatively we could suggest things, which was lovely.  In terms of work that we’ve done in the past at Realtime, it was heavy on environments, which we’ve normally not done.  Usually, we have come in and do a couple of small set extensions and then the creature work or other types of effects work. However, on this we had to handle everything.  Therefore, it was how we split the workflow up and allowed us to keep this idea of grounded reality through everything because we weren’t trying to balance it with another company.  Literally once we set that and talked to Bad Wolf, we were the keepers of that.” 

“We rendered with Karma on this project, so that required us to change a few things and get familiar with that to see how it would go,” states Land.  “The size and skillset of the team definitely changed, and because of the tight schedule to do all of the shots, we did outsource some of it. There was overlapping work in trying to get the shots out in time.  We started to get locked cuts in February 2023 and were delivering from July all the way through September for 10 one-hour episodes.  We joined the show a week before principal photography began. I remember sitting in a restaurant with Realtime's Executive Producer with ‘this is what we need to do now’ list.  It was fine but fast.  During the eight-month shoot, we began working with the art department and some of the asset builds. These things tend to be fluid, so we didn’t quite finish them in their proper state until we were in post.” 

Land worked with a Caer Cadarn interior and courtyard created by North and the art department. “Morlais Quarry in Wales was used for the exteriors, which we built onto with CG for the rest” remarks Land.  “The art department started to give us some hints about what that would look like based on all their research, and we took it on from them to make Caer Cadarn slightly more compelling than it probably would have been back then. It was a collaborative thing.  We were simultaneously doing concept work and taking some of their SketchUp models onto the next stage and popping it back; that worked quite well.” 

Mother Nature was not the most agreeable in Wales and Bristol; the temperature went from 40 degrees to minus six on a night shoot over the 8-month shoot. According to Land, “Our main issue was that we had difficult filming conditions with the weather, so that did compromise us on some of the sites where we were working. The beauty of this was that we got access to and went to some fantastic locations.  I cannot say that they were the most accessible locations on the planet. We were able to concentrate on the CG where it would be seen most. There weren’t lots of silly cleanups. However, we had to make sure to get sufficient material to be able to utilize some of the establishers shot early on in scenes as well as for the later ones if we lost that location, which did happen.”

Hints of contemporary agriculture had to be painted out. “There could be no straight hedges,” reveals Land. “We had to slightly compromise with pine trees, which wouldn’t have been in Britain at that time, but we were facing so many that to a certain degree they had to be embraced but not highlighted.  The biggest thing is we had to build was Caer Cadarn, which is where Arthur hangs out, and then Caer Dolforwyn, where the bad guy lives; both of them had to be spectacular but significantly different so you understood when going from one to the other.  The stronghold in Caer Dolforwyn looks like a wooden version of a Roman villa and is in a lush land.  Then you get Arthur’s war-like stronghold of Caer Cadarn, that while not set in quite as civilized an area, still has a lot of wealth in the ground.”  A different shape language was developed for each. “Anything that was Caer Cadarn was quite rocky and had sharp edges,” Land notes. “When you went over to Caer Dolforwyn, there were rolling hills and a slightly altered color of green, which is much lusher and a bit more manicured.” 

Interiors of Merlin’s Tor in Avalon were built in a studio and the exterior was captured on location where the eight-meter-high sets were extended digitally and subsequently destroyed in later episodes. “If you went up high in the aerial matte you could see industrial areas, so we had to take out all of that and put a river in and extend the settlement back,” Land says.    


Rich application of atmospherics contributed to the environments’ sense of depth.  “We wanted to make sure that we were matching the actual weather conditions where it was being shot,” states Land.  “We didn’t change things too much in that aspect. But because of wide shots, we were constantly adding mist. It couldn’t feel like a mythical place, so we were adding the mist at a realistic level.”  Birds in the shots were created through a combination of real footage, stock footage and CG.  “We were lucky to have three cameras, so they were good at getting us bits and bobs like some nice red kites,” Land explains. “There were doves. No dragons! But we did snakes, which were either being thrown or stamped on.”  

No epic battles occur in the series, which honors the narrative structure of the trilogy.  “One of the questions that we asked early on was if the climax of the series was going to be a battle because that was something we had to be mindful of,” Land reveals.  “The answer that came back was, ‘It wasn’t.’  The climax is different because it leads into another series and it’s based on the books, so we’re not at that battle stage yet.  We added quite a lot of dead bodies and some crowd replication in the conventional sense.  20x40 greenscreens were put up, we moved the crowd around, and projected them onto cards. It was a moving shot.  That was the most we had to do.  It was strange because we expected when coming onboard the show that crowd replication would be a big thing, but as a matter of fact, it wasn’t this particular series.”  

The climax of The Winter King is a reversal of the legendary act of pulling the sword out of the stone. “If you have a big stone wall, you’re clearly not going to bash your way through it,” Land observes. “No matter how magical you are, it’s going to look ridiculous. The route that we went down was Arthur pushed his sword into the stone, which is the reverse of the legend where he takes the sword out of the stone and becomes king.  The idea is that Excalibur would vibrate and the vibration would destroy all of the mortar between the bricks, which would come crashing down.  That’s how a man and sword can bring down a big wall! Getting that concept across and learning what we wanted to do with that was one thing.  The next thing was trying to make sure that it looked and felt absolutely real.  We were quite happy about that.  That was outsourced for its final simulations because we wanted to give it enough time to be done properly while we were trying to get everything else out.  That was a lot of Houdini work and then they had to build the wall.  It was quite a big task”. Excalibur is a character in its own right.  “It’s never about showing anything absolutely for real.  It’s always about inferring what could happen.”

Trevor Hogg's picture

Trevor Hogg is a freelance video editor and writer best known for composing in-depth filmmaker and movie profiles for VFX Voice, Animation Magazine, and British Cinematographer.