Digit feels the heat with a behind-the-scenes report on the visual effects for Hellboy.

Due for release in the UK in September, Hellboy – like Spiderman, Superman and The Hulk before it – is another example of a comic-book hero brought to cinematic life.

Based on the Mike Mignola’s Dark Horse Comics series of the same name, Hellboy is a supernatural, action adventure directed by Guillermo del Toro of Blade II fame. The film begins back in 1944, when evil madman Grigori Rasputin and a team of Nazis attempt to open a portal to Hell and unleash the seven gods of chaos in order to turn the tide of World War II in their favour. Committee

Thwarted in time by the Allies, one creature nonetheless appears out of this portal – an infant demon complete with horns, a tail and red-coloured skin. He is named Hellboy, and is adopted by Professor Bloom, founder of the underground operation Bureau for Paranormal Research and Defense (BPRD). Hellboy (played by Ron Perlman) grows up to be a fighter of evil, working alongside some equally unique colleagues at BPRD – merman Abe Sapien (Doug Jones) and the pyro-kinetic Liz Sherman (Selma Blair).

When Rasputin resurfaces and attempts to finish what he started back in the ’40s, Hellboy and his friends must face the evil occultist in a supernatural showdown that naturally sees the fate of the world hanging in the balance.

Enhancing the film’s fantastic use of costume and make-up, CG and visual effects were used aplenty to bring to life the comic-book characters and recreate the locations for the story. Hollywood-based visual-effects specialists, Eden FX created over 200 such shots for the film – making it the company’s biggest film project to date.

Having made its name in episodic television with award-winning effects for show such as Star Trek Enterprise, Navy:NCIS and Jag, Eden FX was formed in 2000 by John Gross and Mark Miller. The company specializes in visual effects featuring 3D animation, 3D tracking and compositing, plate enhancements and set extensions, and full CG environments.

Hellboy’s visual-effects supervisor Edward Irastorza invited Eden FX to pitch for a number of shots on the movie. From an initial 80 shots awarded to the company, the number quickly grew to a final count of 208. “We became the ‘go to’ company for more shots because we were able to get quick approvals and were able to move through shots,” explains John Gross, co-president of Eden FX and visual-effects supervisor for the project.

“We would get sign-off on many of our shots at a weekly screening with Guillermo (del Toro), and then Ed (Irastorza) would talk to us about some more shots that he wanted to give us. Then we would take a look at resources and such to determine what additional shots we could comfortably take on.”

The first batch of shots the Eden FX team worked on were several sky/snow replacements and enhancements shots, plus creating Hellboy’s tail in shots where a physical one hadn’t been used, Abe Sapien’s eye blinks and Kronen’s eyeball replacements. Of these, the sky/snow replacements were the hardest says Gross, because of the amount of roto work and tracking required.

“As is often the case, one would never guess two of our most difficult shots from watching them in the film,” adds Steve Pugh, Eden FX’s visual-effects producer for Hellboy.

“In one sequence, shot over several days in and around a cemetery in Prague, it snowed every day except one. We were asked to replace the barren dirt landscape and clear sky behind the actors with a snowscape and storm clouds, to match the rest of the sequence,” he explains.

“In one of these shots, the camera pans from the front bumper of a truck driven by Agent Myers (played by Rupert Evans), around the side of the cab, and then crash-dissolves through the side of a crate being carried in the truck’s bed to reveal Hellboy sitting inside. Digital artist Mike Stetson had to rotoscope around the truck – and its antennas, windshield wipers, and various boxes – in order to replace the background, and then had to match his 3D environment to the shaking, bumping camera motion. Unfortunately for Mike, his environment is so convincing that most moviegoers will never know the weeks of pain that went into that shot,” he says.

Irastorza was extremely well-organized when it came to managing the shots requiring visual effects work, says Gross. Each shot was provided with a description, notes and a frame count. “Storyboards were also provided by Ed and his team as a jumping-off point, says Gross. “Yet most shots were conceptualized by sitting down with Guillermo and Ed, and talking it through.”

Shots were then distributed among the Eden FX artists based on their workload and specialities. Animatics were created for the sequences that involved animation – and were then cleaned up before being shown to the client in a ‘better than animatic’ form, says Gross.

To complete the effects, Eden’s artists relied on the studio’s main 3D tool of choice – LightWave – along with Photoshop CS, and Maya. Digital Fusion, After Effects, and Combustion were used for compositing, and Boujou for tracking.

Once shots were completed, QuickTime movies were generated and put on an FTP site for the client to access. These would be spliced into the latest cut of the movie for viewing by the director and film’s visual-effects supervisor.

“Once or twice a week, we would then view the shots on film with Guillermo, Ed and others. At that point, Guillermo would either approve the shot or give some final feedback, and the process would begin again,” explains Gross.

“The wonderful thing about working with Guillermo and Ed was that they signed off on shots quickly and so we were able to move on to more shots,” he adds. “Sometimes in film work, shots are noodled for a long time because the deadline is further off and shots are changed for the sake of making them different. When Guillermo or Ed had notes, it was to help make the shot better.”

The seven months spent completing the 208 shots for Hellboy taught the team how to handle a major film project effectively, says Gross. “The organization of our team by Steve Pugh and Mike Tuinstra (visual-effects co-ordinator) was the key that made it work so efficiently through our existing pipeline.”

Compared to the studio’s episodic television fare, working on a major film afforded the visual-effects artists more time, and therefore more budget, to play with in order to perfect their shots.

“On episodic schedules, you sometimes only have a few days for a shot. When you can spend more time on a shot, you have the ability to have more eyes see it, and to test out a couple of concepts and refine them,” explains Gross. “Of course, you have to build higher-resolution models and such for film, and tracking is a bigger issue, because when something is 40 feet across, it’s easier to see mistakes, yet besides that, the same concepts exist between television and film.”

Abe Sapien

Abe Sapien’s character was brought to life thanks to prosthetic makeup by Spectral Motion.

“This was beautiful and incredibly detailed – right down to flaring nostrils,” says Steve Pugh. “However, the design meshed so closely to the actor's features that it would have been too bulky to build in a mechanism to make the eyes blink the way the director wanted.”

Instead Eden FX was asked to add digital eye blinks to Abe whenever he was onscreen for an appreciable length of time (which, says Pugh, ended up being almost 50 shots). John Teska, Eden FX’s lead digital artist on the film established a blink look using a regular eyelid and a translucent second membrane.

Using a 3D scanned head to track into the live-action plate, he rendered the blinks out of LightWave and composited them using AfterEffects, where he also added subtle warping to the face around the eyes to create different emotions depending on the scene. The end result, while subtle, brought a lot of life to the character, says Pugh.

One of the largest sequences Eden FX worked on for the film was an underwater sequence that sees Abe Sapien encounter two demons. Although Tippett Studios had produced many completely CG shots of the full-body Abe Sapien, several shots had been filmed of Abe on a dry soundstage and Eden’s artists were called on to give these a murky underwater look.

“Complicating this sequence was an important story point – Abe is wearing an amulet on a lanyard around his wrist, which contains a religious relic (a finger bone according to Hellboy) to protect him,” explains Pugh. “Because the shots were filmed ‘dry for wet’ on a stage, gravity would have made a real amulet hang off of his wrist, instead of floating like it would underwater. So, we also had to track a CG lanyard and amulet onto the actor’s wrist. Eden FX’s Pierre Drolet built the amulet with the pinky bone inside in LightWave, and Motion Designer was used to give the lanyard the right physical motion to make if feel as if it were moving through water, dragging behind his hand when he swam, and settling down slowly when he was still.

Eden FX’s Mike Stetson created the underwater environment, with multiple layers of silt and particulate matter floating in front of and behind Abe, papers floating in the background, and bubbles coming up from Abe’s mouth while he swam. He also added a subtle displacement to the image in those parts where Abe’s swimming caused ripples in the water.

At one point, the amulet snags on a pipe and breaks, leaving Abe defenceless against the demons. For these scenes, digital artist Fred Pienkos animated the amulet model, using Motion Designer for the snapping lanyard, and hand-animating the amulet itself as it falls through the water and between the gaps in an iron grate, as Abe tries frantically to retrieve it.

Hellboy’s transformation

One of the longest sequences Eden FX worked on occurs towards the end of the film. In this part of the story, Hellboy is forced to transform into his true self, the demon prince who can bring forth the end of the world by freeing the demons Ogdru Jahad.

Upon uttering his demonic name, Hellboy’s horns grow out to their full size, his breath turns to hot smoke, and a crown of fire appears over his head.

To create the transformation, Eden FX had to track in digital breath and a volumetric crown of flames, as well as steam and glowing energy being emitted from Hellboy’s stony right arm.

John Teska, Eden FX’s lead artist on the film, developed the look of the crown and breath, and constructed a ‘kit’ for each so that the company’s other artists were able to use the same 3D assets and techniques.

“This allowed us to ensure that all of the shots were consistent in their look and once he had fine-tuned the look of things to a point where he, Ed (Irastoza), and Guillermo (del Toro) were satisfied, we were able to complete the sequence quite rapidly,” explains Steve Pugh, Eden FX’s visual-effects producer.

The sequence was accomplished using a combination of 3D and 2D techniques. Elements of Hellboy’s fiery crown were created in NewTek's LightWave, using several Hypervoxel layers – multiple separate flame and smoke elements explains Pugh.

Hellboy’s smoky breath was also a Hypervoxel element, with LightWave's built-in particle system used to time the smoke to actor Ron Perlman’s breathing.

“Inside LightWave, these voxels and particle emitters were parented to a 3D scan of Ron Perlman’s head in his Hellboy makeup, so that each artist could hand-track the crown and breath to follow his movements through the scene,” says Pugh. “Once rendered, these elements were blended together in Adobe After Effects or Eyeon’s Digital Fusion, according to an established ‘recipe’ to ensure continuity regardless of the artist’s preferred compositing package.”

The same technique was used to replace the prop arm worn by Perlman with a smoking, glowing version that was created based on another 3D scan, again using voxels to emit smoke from the glowing cracks. The CG arm also had articulated fingers so that close-ups are more lively.

“I would have to say that the Ogdru Jahad sequence was the most exciting part of the film for us. So many of the effects we were called upon to handle for this project were ‘invisible’ effects, which are very satisfying in their own right, but this sequence gave us the opportunity to work closely with the director to bring something fanciful and dramatic to the screen,” says Pugh.

In the comic books, Hellboy’s feet are small and hoofed like a goat. Recreating this look proved quite a challenge for the filmmakers. For the shots of Hellboy in his room, Ron Perlman was filmed wearing greenscreen leggings, and Eden FX was charged with providing his legs and feet.

The team went through several revisions of feet to ensure they suited the look of the character and the actor. In the end, what worked best according to John Gross, was a cow-like foot – even though this differed from the comic book illustrations.

Under the yoke: challenges in 3D

“A shot from the final sequence of Hellboy proved to be one of the most technically challenging I’ve ever attempted,” says Eden FX artist Eddie Robison. The shot in question sees Hellboy locked in a sort of ‘yoke’ mechanism – his head and hands are seen poking through a wooden restraint that has solid-looking metal hinges locking it down. The director wanted Hellboy to snap open the yoke at the end of the shot.

According to Robison, the real challenge of the effect lay in removing the practical hinges that were already there. The camera was moving and rotating while Perlman as Hellboy did the same at different rates, which meant the perspective was constantly changing, explains Robison.

Complicating matters further, the wood underneath the hinges was heavily scored with a distinctive grain.

“I started with the easy stuff first – creating the hinges in CG and animating them flying open. I used a still of the real hinges for textures and had a flat coloured base for the wood itself to catch the shadows on a separate render pass,” explains Robison.

“To remove the real hinges, I began by taking a still from the last frame of action before the CG elements took over and I did a perspective warp on that image to flatten it out. In Photoshop CS, I painted out the hinges taking care to keep the wood grain intact so that it would not make an obvious jump when the CG elements started. I then ‘dewarped’ that still image using the reverse method used to flatten it out and four-corner tracked it back over the plate using Digital Fusion. This proved to be difficult due to all the perspective shifting but several attempts later, I had a solid track,” he says.

Robison then added the 3D hinges and shadows back on top of his clean wood yoke, and popped them off one at a time using a series of hand-cut roto mattes to reveal each in succession. “The result was a fully photoreal shot that the audience would never had appreciated as an effect,” he says.