London VFX studio Double Negative worked closely with award-winning director Guillermo del Toro to translate his monster visions into over 1,000 shots for Hellboy 2: The Golden Army.

Even after a summer packed with comic-book-to-blockbuster movies, there’s plenty for the most jaded film fan to enjoy in Hellboy 2: The Golden Army, director Guillermo del Toro’s sequel to his 2004 sleeper-hit Hellboy.

Based on Mike Mignola’s comic-book hero, Hellboy – or Big Red, as he’s know to his friends – is a wise-cracking, gun-toting demon with a penchant for cats and Cuban cigars.

Bright red in colour, with sawn-down horns, a tail and oversized right hand, Hellboy is once again played to perfection by Ron Perlman.

Working with his fellow supernatural beings at the Bureau for Paranormal Research and Defense, this time around Hellboy is faced with a power-hungry elf named Prince Nuada who wants to break a historic truce between humans and the fantastic creatures that live invisibly among them.

The film features an array of bizarre and freakish creatures from the fertile imagination of Guillermo del Toro, who won great acclaim for his dark fantasy Pan’s Labyrinth.

London-based visual-effects house Double Negative was responsible for bringing these monsters to life. As lead visual effects supplier, Double Negative delivered 1,050 shots for the film – making it the studio’s biggest job to date.

“Being awarded the whole film was a very exciting opportunity for us here at Double Negative,” says Andrew Chapman, CG supervisor.

“Most of the time we only get to work on small parts of a big feature like this, and you’re often a little envious of the sequences or creatures that the other vendors end up with.”

Being awarded the whole project meant that the Double Negative team was involved from the very start – “so we knew that every crazy idea and creature pouring forth from Guillermo’s head would be ours to deal with,” says Chapman.

Working with the film’s visual-effects supervisor Mike Wassel and visual-effects producer Lucy Killick, the Double Negative team was led by senior visual-effects producer Steve Garrad, Andrew Chapman and his fellow CG supervisors Adrian De Wet and Justin Martin, along with animation supervisor Eamonn Butler.

“The biggest challenge for us in getting started on Hellboy II was the scope of the creature work,” says Chapman, whose past film credits include Troy, Charlie and the Chocolate Factory and The Reaping.

“Although Double Negative has worked on some massive shows in the past, our primary focus has been environment and effects work, so suddenly dealing with dozens of different creatures and digi-doubles on a 1,000 plus shot show was a little daunting. We had to really plan things out and break it down into teams to ensure nothing was overlooked or got left behind,” explains Chapman.

Working for nearly 18 months from bid to final delivery, the studio’s work on the film ranges from fully-CG creatures, CG digi-doubles, digital set extensions and matte paintings to atmospheric effects including steam, smoke, fire and water.

The project was divided across various teams, some on a per-sequence basis and some for the specific nature of the work, explains Chapman.

There were major teams for the three largest sequences – the Elemental, the Tooth Fairies and the Golden Army – with smaller teams handling sequences such as the Troll market.

Software multi-tasking

Maya is the tool of choice for Double Negative’s 3D pipeline, although zBrush, Softimage|XSI, Mudbox and Cyslice were also used for modelling. Some of the effects work was also created in Houdini before being taken back into Maya for lighting and then rendering out to RenderMan through a custom translator called Rex.

Fluid simulations were rendered through a proprietary voxel called DNB. The team used a number of custom tools on the project – including, for the first time, its new fluid simulation engine Squirt, and its particle system tool dnSwarm.

“Squirt worked wonders for all our smoke, dust, steam, fire, oil and goo effects,” says Chapman. “The combination of Squirt and DNB means we’re able to churn out these effects passes a lot easier these days, which is great because adding them really helps bind the CG into the photographic plates.”

Compositing was done in Shake, with custom tools tagged on. The creatures’ design had largely been completed by del Toro and his team of concept artists during pre-production in LA, but some refinements became necessary as the Double Negative teams worked to bring them to CG life.

“Guillermo was appreciative of the problems we foresaw and was eager to work through the process, where other directors might have been more resistant to change, only understanding the problems once we’ve been far enough through the process to show them things that don’t work so well,” says Chapman.

Building a beanstalk

One creature that proved challenging was the Elemental – yet the sequence turned out to be one of most rewarding to work on, says Chapman.

A fully animated CG creature made of leaves and vines, the Elemental bursts through a New York street having grown from a seed pod in a sewer. Once above ground, it grows like a giant beanstalk until it is nearly 90 feet tall. The biggest challenge of this sequence was conveying the look and scale of this creature while staying faithful to the director’s vision.

“We initially explored using texture to sell his scale, but we were still really struggling,” recalls Chapman. “The idea we finally settled on was to give him a jacket of foliage.

"This served to break up and make his silhouette more interesting, as well as helping the scale – you can relate to the size of vines and leaves – and making his motion more interesting as they flap around.”

He continues: “That design process was a real collaboration between the artists here and the director – at that stage we were only tasked with building the basic creature, but we knew it wouldn’t really shine in the end without something extra, so we took the initiative to explore the creature design and come up with something – and thankfully it worked out quite well.”