When director Gareth Edwards needed a CG cast of thousands on a tight budget for his BBC Two documentary on Attila the Hun, he found that it was easiest to build it himself.
Faced with the challenge of recreating historical battle scenes with casts of thousands, most Hollywood directors would turn to one of the big VFX studios wielding a copy of the crowd simulation software Massive.
But for Bafta award-winner Gareth Edwards, equipped with only a British TV budget, this simply wasn’t an option.
Instead, he used a combination of After Effects and Photoshop on his home computer, loads of ingenuity and hard graft, to personally create the 260 HD visual effects shots required for his TV epic on Attila the Hun – all in just five months.
Attila the Hun aired on BBC Two in February, and will be screened in the US on the Discovery channel later this year. The hour-long programme was made for the cost of the average documentary.
The programme was filmed in Bulgaria with a small cast and little post-production support. “The story of Attila obviously involves lots of big battles. In fact, the final battle in the film supposedly had more people fighting than any other battle from ancient times – between 30,000 and 250,000 depending on who you believe,” explains Gareth Edwards.
“With my background in visual effects, the producers were keen for me to integrate this more than you could in other TV shows, to help build the scale of the world as it was back then. Personally, I saw it as a great opportunity to do a mini Lord of the Rings,” he says.
Budget was the main reason why Edwards had to take on all the visual-effects work himself. “It was a case of either do it in the computer later or not do it at all,” he explains.
“And I really didn’t want to compromise, so I guess I ended up taking on more work than I originally anticipated.”
Yet the situation wasn’t without its advantages, says Edwards. “There’s an efficiency that happens when there is no middle man between the visual effects and the director.
"You can literally stand on set and have an idea, you don’t have to ask permission, you don’t have to get financial approval, you can just decide that you can solve a problem with CG and keep the film moving,” he says.
Edwards’ original schedule aimed to create a shot a day over three months of post, but extra shots were added on location, either to help keep the scale of the film believable or to fix subtle things that occurred during filming.
In the end, the visual-effects shot tally rose to 260. The programme began with two months of pre-production spent scriptwriting, storyboarding, location scouting and casting.
With the show commission by the BBC’s factual department, historical accuracy was paramount. The script was checked and approved by a leading expert on Attila the Hun, and production designer Alan Spalding and his team also extensively researched the period.
The programme was filmed over three weeks on location in Bulgaria – chosen partly because Attila’s army travelled across the country, meaning that its geography was historically accurate, and partly because Edwards could make use of a Roman back-lot belonging to a film studio based in the Bulgarian capital, Sofia.
Back in the UK, editor Colin Goudie worked on the final cut, while Edwards created previzualizations of the missing CG shots on his laptop for the producers to sign off.
Then he retreated to his home office for the next five months, to create the visual effects, using a predominantly Adobe-based pipeline.
VFX pipeline Working from a high-definition (720p) QuickTime file, Edwards created a timeline of the film in Adobe Premiere, so that he could watch it in high-definition.
“I just used a cheap Blackmagic Design Intensity card for this,” he says. The video footage itself had been shot with 35mm adaptors for a film look, which gave it a very narrow depth of field. As a result, tracking shots with added CG was quite a challenge.
Fortunately, says Edwards, Imagineer released its tracking software Mocha at the start of the post work. “Instead of tracking points, Mocha tracks parts of an entire image,” explains Edwards.
“This quickly became my main way of tracking shots.” He explains a standard day’s routine in the post-production: “First I’d find the shot I needed to do on the timeline. I’d then export the ‘plate’ or background image into After Effects and spend about half an hour or so, tracking the shot and very crudely creating a rough version of what the shot might look like.
“I’d then import this back into Premiere and watch it in the context of the actual scene. This was very important, as it’s easy to start going down the wrong path with a VFX shot. You can spend a long time adding details that the audience will never see.
“You can check if your idea is going to work, and how dark or light things need to be, as well as composition and camera movement. With so much work to do, making sure I didn’t waste time on things that weren’t important became crucial,” he says.
Once happy with the shot, Edwards would go back and add more detail in After Effects, re-render and assess it again.
“The great thing about Adobe is that every time you hit render, it automatically updates the timeline in Premiere to include your new shot. So, if I did a lot VFX shots in a day, and hit render overnight, in the morning the timeline would automatically contain all the new sequences,” he explains.
“There was no way I was going to be able to make all the shots as good as Lord of the Rings, but it was important that they were consistent, as it’s no good having an amazing shot if the following shot looks rubbish.”
Creating battle scenes without a cast of thousands or a copy of Massive was a major challenge for Edwards. The large armies of the Huns and the Romans storming across the countryside to face one another in battle had to be carefully planned from the very earliest stages of the production.
Artist Gregory Fangeaux created storyboard sequences for the two major battles. “With a lot of the scenes, you might not need a specific storyboard,” says Edwards.
“But you’d be crazy trying to shoot battles without carefully planning, as the stunt department need to understand what you’re trying to do.”
Edwards adopted two approaches to recreating the battle sequence. The first was to use lots of 3D character models created in 3DS Max on run cycles (see box, right), while the second involved a giant green screen used during filming.
“On the last day of the shoot, the main film crew shot the whole end sequence against the greenscreen with Attila (Rory McCann) and the stunt guys, with a few tracking markers on the green to help me later replace it with a different background,” says Edwards.
The background needed to have around 30,000 people fighting in it. To help achieve this, a couple of Edwards’ friends – Luke Wilmot and Tony Gilbert from Shadow Industries – flew to Bulgaria to shoot the stunt work.
They filmed four stuntmen doing a generic fighting action. “This never really repeats itself, so you can copy and paste those same four guys, and as long as you offset the timings – so they didn’t look like synchronized swimmers – you have a giant army,” explains Edwards.
“Once you’ve duplicated them enough, you then have to add all the subtle details, such as smoke, shadows and glints, to help sell the realism of the effect.
"Once this was done, I essentially had a giant (5,000-pixel) background footage that I could drag and drop into any shot. This process was then very quick. The irony is that the end, battle looks the most ambitious and difficult sequence in the film, but for this reason was probably the easiest to do.”
Edwards says that there’s a big difference between CG that looks real and CG that looks right.
“There’s a lot of weight placed in CG to make everything look ‘real’, but that doesn’t mean it looks good. If that were true, then every home video on YouTube would be winning an Oscar,” he says.
“You have to tread a fine line between it looking believable, but also beautiful, and this is the hardest skill of all.”
A kind of magic
According to Edwards, one of the advantages of creating visual effects for TV shows is that they are not subject to the close scrutiny that feature films receive.
So it’s possible, he says, to get away with far more, as long as you concentrate attention on the areas of the screen that the audience’s eye is drawn towards.
“It’s like sleight-of-hand coin magic, where you’re trying to distract the audience and make them not notice all the smoke and mirrors you used to create the shots.
"Most shots in the film only last about three seconds, yet that’s the equivalent of 70 million different pixels all flashing on and off really quickly. The human brain can never take all that information in,” he explains.
“For instance, if you were to flash this whole page in front of someone’s eyes for just three seconds, they would never be able to read the whole thing, only a sentence or so.
"The same is true of film making, the trick is to put your ‘magic’ only in the area that the audience looks at. Doing that is half the (CG) battle,” he says.
Battle scenes created in 3D
“A little trick I like to play to get inspired is to watch a Hollywood movie that’s doing similar shots to what I have to do, and try and convince myself that those guys did it in just a day,” says Edwards.
“At first it seems impossible, especially for sequences where thousands of people charge across a field. But then when you think about it a bit more, you begin to realize that in fact, all that is really going on is lots of little ‘run-cycles’ being applied to 3D characters.
“Other tricks were needed to help sell the illusion,” he continues. “Various passes such as dust, soft shadow and cloud shadow passes were then all combined to create the final shot.”
Creating convincing armies for the film was a key challenge. “While most people don’t have a point of reference for what a dinosaur looks like or what a meteor impact would look like, everyone knows what a bunch of guys in a field look like,” says Edwards.
While 260 VFX shots may seem like a “killer amount of work”, Edwards is quick to point out that at least a third involved mundane tasks such as wire removal or painting out elements that had crept into shot such microphone booms or catering vans.
“For many shots I had to rub out the modern items and replace them with extra bits of field or buildings,” recalls Edwards. “A common one was catering trucks, as they need to be as close to the set as they can to reduce the time it takes to set things up.
The film was shot on location in Bulgaria, which was much cheaper than filming in the UK, says Edwards. This in turn meant he could hire a larger crew and more background artists.
“The more talented people you have around you, the better your chance of getting it right first time – you only have a few goes at each scene, then you have to move on to the next one,” he explains.
Project: Attila the Hun
Client: BBC Factual
Software: Adobe After Effects, Adobe Premiere Pro, Apple Final Cut Pro, Adobe Photoshop, Autodesk 3DS Max, Imagineer Mocha