Tim Burke spent the last ten years immersed in the magical world of Harry Potter, a world that could not have been created without visual effects. He was visual effects supervisor at Mill Film for the second film, Harry Potter and the Chamber of Secrets, and has been the visual effects supervisor on each film since in the series of eight, receiving an Oscar nomination as co-visual effects supervisor for the third, Harry Potter and the Prisoner of Azkaban. Burke led the efforts for the final four, receiving another Oscar nomination as senior visual effects supervisor for last year’s Harry Potter and the Deathly Hallows: Part 1. Before Potter, Burke began his career as a digital effects compositor at Mill Film, becoming a visual effects supervisor with the 2000 film Gladiator, for which he won an Oscar for best visual effects. In addition, he received a BAFTA nomination for that film, and five additional BAFTAs for the Harry Potter films.

Burke shares his fourth Oscar nomination, for Harry Potter and the Deathly Hallows: Part II, with Double Negative visual effects supervisor David Vickery, Moving Picture Company (MPC) visual effects supervisor Greg Butler, and special effects supervisor John Richardson. Directed by David Yates, this last film in the Harry Potter series is arguably the best reviewed and has become the third-highest grossing film of all time worldwide, edging out this year’s Transformers: Dark of the Moon, now in fourth place. On February 12, Burke, Vickery, Butler, and Richardson won the BAFTA award for Best Special Visual Effects.

Watch the Harry Potter and the Deathly Hallows: Part 2 VFX bake-off reel at Double Negative’s website.

Film & Video: Congratulations on your BAFTA award.

Tim Burke: Thank you. It was the fifth nomination and the first one we won.

Why do you think this film won?

I think a lot of people believe this film had the best effects in it, and there’s a little bit of people realizing this was the last Potter, so there might have been a little sense of honoring the series as well.

In what way did this film have the best effects of the series?

It was more of a spectacle. It was the final chapter of the saga, the death of Voldemort, the battles. We’d never been able to create sequences on that scale before. Before, the films had been fairly contained. This gave us an epic sense of the world around Hogwarts rather than inside Hogwarts.

In a way, because they take place more in the real world, they were more like what we think of as visual effects, weren’t they?

Yes. They were traditional in the sense of creating worlds, crowds, creatures. People focus on the obvious effects – the giants, the CG spiders, the dragon. But in addition, we have the world and the landscape the battle took place in. We had good old fashioned action sequences with CG characters and live-action characters set in a virtual world created to look as photographically real as possible.

Do you think people have discounted the “magic” effects through the years?

I think so, sometimes. Also, some people think we were doing the same thing over and over again. Talking paintings. Wand effects. So, I think perhaps there was a sense with some people that we were doing the same thing every time. Hopefully, the last film showed a bigger world no one had seen before, and brought so many CG characters and creatures into the storytelling. The visual effects were more obvious without being live action with magical effects on top.

Did it help to work with the same studios you had worked with before?

Having the luxury of working on several films together in the same series does help. You build up relationships, learn the strengths and weaknesses of different studios. These were mostly Soho-based shows. We were able to use the best visual effects supervisors and artists at the key vendors and build a team to deliver the caliber of work everyone expected.

It was an incredibly unique experience working with so many of the same team – the visual-effects artists, but also the special effects, wardrobe, creature design. The first AD was the same on the last four films. We had the same director for the last four films. Having that longevity allows you to build relationships you usually never get on a film. So often you have to build a relationship quickly and then you’re done. But this was great. We became friends far beyond working on the films, and that in itself was a great experience.

I did get a chance to work with new companies, too. Working with Tippett Studio and Matt Jacobs was a really great experience. And, we also had other UK vendors, Rising Sun in Australia, and a couple smaller companies.

You had always used miniatures for previous shows. Did you do that again for this one?

We didn’t use any miniatures for Hogwarts. It was the first time we did away with the 24th-scale model. We used a third-scale viaduct for the sequence with the giants. We scaled the architecture they were running on to make the actors look taller. But we didn’t use miniatures to recreate Hogwarts.

Why was Hogwarts always a digital set this time?

It was a big change, a big decision that we made before starting the film. We were still working on the sixth film [Harry Potter and the Half-Blood Prince] and in discussions with the director and producers. All we had was the book. No script. We realized how much a part of the film and the story the school had become. David [Yates] wanted the freedom to fly the camera outside the school, inside the windows, explore the school as part of the developing battle.

Having worked with miniatures in the past, one big 24th-scale and bespoke models at different scales for key areas, we knew it would be a daunting task to build all those miniatures and nest them into wider shots. Double Negative had technology that we had used successfully on Half-Blood Prince to rebuild the whole of London. It was time to throw away the model.

We could previs, design the resolution we need to build, then plot and plan the school build at different resolutions to do everything David [Yates] wanted. He could move the camera from the mountain into the window to a camera move on a stage set. We had all that architecture.

It sounds like the virtual environments gave you more flexibility.

That was exactly it. That was the key. David actually invented shots later in the process. We were designing end shots for the death of Voldemort a couple months before we delivered the film. We were rendering shots, then spitting them out in overnight renders. There’s no way we could have done that without the virtual environments we had prepared.

Did you know you’d be designing shots at the last minute?

There were certain areas of the film unresolved and because of the virtual environments, [David Yates] realized we could recreate shots quickly. The key thing that changed was the death of Voldemort. That happened after we had locked cuts. We had done some screenings and realized we needed a more epic ending. So we redesigned the sequence and thankfully with the digital assets we could recreate the environment. We projected some elements of Ralph Fiennes onto geometry of him and added those to the shots, and for a couple shots had to use a full CG Voldemort. It happened way past the 11th hour. The shoot had finished 12 months earlier, so it was long past the point of pick-up shots. We had to take materials from other shots and recreate him.

The advent of digital cinema has allowed processes to go right to the wire more so than anything, and strangely enough, directors do seem to push further each time. You get to the point where you say, “That’s really it,” and no one believes you. I think David [Yates] would still be working on the film now if he could.

Did you design the “roller coaster” sequence through the Gringotts bank with stereo 3D in mind?

When we shot the film, we didn’t yet have the decision about stereo. We were shooting sequences and didn’t know it would be post-converted. But we designed that sequence in previs to be as much of a roller coaster ride as we could. When we knew the film would be in stereo, we knew certain shots could be delivered by visual effects, and that was one. We had shot the actors on a motion-based gimbal. We extracted those elements and re-projected them onto geometry. The environment was all 3D so we could re-design the shots to push the stereo roller-coaster ride experience and make the audience become a participant in the ride. That was great fun. We did several other sequences where we took over, about 200 shots, and rather than having a post conversion, delivered full 3D shots.

Which shots in the film are your favorites?

Funnily enough, I think the sequence of the shield forming and the destruction of the shield. Even though they weren’t perhaps the most complicated, they were some of the most beautiful. As Voldemort arrived with his army on the hillside, the teachers went into the areas of the courtyard and created a magical shield that enveloped and protected the school. We art-directed the shots at Double Negative and they are elegant.

It took a long time to create the magical shield. Then Voldemort bombarded the school and destroyed the shield. We wanted to give that an epic scale. We referenced the Hindenburg airship disaster, when it went up in flames, to get the scale of the flames and burning materials. That was the reference for pieces of cloth-like fire that dropped down onto the school. It was magical – not in a Harry Potter sense. It was beautiful and shocking at the same time. Those shots were completely CG and had a big design aspect, which is rewarding.

Of course, all the fighting action sequences were great fun. Getting the giants to work by using live-action actors and changing their faces with CG helped us not to have to create full CG characters. We used scaling and oversized people. MPC changed their faces so they didn’t look human.

And I’m not forgetting the dragon that D-Neg created. We had to emphasize and feel sorry for this 60-foot dragon through pure performance. We found reference from badly treated real animals and translated that body language into our character. He was trapped. Unable to fly. Partially blind. And he had been down there his whole life. It was important to emphasize that so you wanted him to escape and when he did, he flew with majesty and pride. That was a lovely story to roll into the character of the dragon.

Did you have other CG characters in the film?

We had the dementors again – Rising Sun did those. Framestore did the giant spiders. That has a sweet backstory. Andy Kind, the supervisor who did the spiders, was the one at Mill Film who had worked with me on the spiders on the second film nine years back. Mill Film closed down, so those spiders no longer existed. He rebuilt them by referencing footage from that film.

Framestore did the same thing for the Chamber of Secrets that also featured in the second film, but had since been long destroyed. We completely built that as a CG environment. Andy and his team built what was originally a Framestore sequence again by referencing footage from the original film. They used as many textures as I could get re-scanned from the original negative, and remodeled everything from scratch.

Soho has changed a lot since that second film, hasn’t it?

We’ve seen a lot of changes in the visual-effects industry, especially in London, in the past 10 years. When I was working on the second film at Mill Film, which closed shortly after the film released, London was a growing hub of talent with four or five companies competing against each other and against America. In the last 10 years, the talent and capability has expanded and the volume of work that can go through is on par with any other major cities – LA, San Francisco, or Weta [in New Zealand]. We have a hub of great visual-effects companies producing great work now, a great industry that you can almost say has grown on the back of the Harry Potter films. And the Harry Potter films are a great advert for quality of their work.

What trends are you seeing in visual effects now?

It’s an interesting year this year. There have been a lot of superhero films in a lot of styles, some better than others, which is often down to the script. But this year, there is a more diverse range of films, more than before. We have more art-directed visual effects than before. Not just big effects – it’s the subtle use of invisible effects in storytelling. As good as the robot-based films are, it’s nice to see more diversity. The work on Tree of Life is beautiful, fantastic work. Very original. We have the amazing work with the motion-captured apes [from Rise of the Planet of the Apes], which are the main characters in a story that couldn’t have been filmed without those CG characters. The apes are the actors. Hugo is beautifully art-directed and designed and the visual effects are part of the storytelling in the same way the work in Potter is art directed and part of storytelling. These films open up the competition and open up our world more. I hope this will continue. We can do most things we’re asked to do, but we need good scripts and good ideas. I think that’s what’s been good this year: more interesting scripts using visual effects with more diversity.

How does it feel to be away from the world of Harry Potter now?

It’s really difficult trying to give you sensible information. It feels like a long time ago. It was quite an interesting challenge to come back into the real world. So it’s nice having these awards ceremonies. It brings it back. It was such a great experience, and we were so sad when it was finished. This is a nice timely reminder of what we were involved in.