A Friendship Forged in Fire
Karen Moltenbrey
April 5, 2019

A Friendship Forged in Fire

“If you love someone, set them free….” That premise was at the heart of The Hidden World, the third and final installment in the DreamWorks Animation film series How to Train Your Dragon, loosely based on the books by Cressida Cowell of the same name, about an insecure young Viking and his beloved dragon Toothless, as they help each other grow and mature, and eventually fulfill their destinies separately.

Storywise, the third installment, released February 22, picks up shortly after How to Train Your Dragon 2 (2014) left off. The young Vikings are still dragon rescuers, not dragon slayers, as they first began in the original film from 2010. The dragon Toothless and the Viking Hiccup, now ruler of the tribe along with the fearless Astrid, are members of the Dragon Riders squadron, who continue to rescue captured dragons and bring them back to the village of Berk to live. But flaws within the chaotic yet utopian society soon become apparent: There just isn’t enough room on the island for both humans and beasts to life comfortably. So, Hiccup embarks on a mission to find the mythical Hidden World, fabled to be a safe haven for dragons. Meanwhile, the evil Grimmel, who longs to capture Toothless, a Night Fury – believed to be the most feared of all dragon species – and eradicate all dragons forever. 

Hiccup and Toothless remain loyal friends, but… Toothless meets a white Fury, called Light Fury by Astrid, and the two strike up a romance as only dragons can. However Grimmel captures Light Fury in attempt to force Toothless into becoming his alpha dragon. Hiccup and the Dragon Riders attack Grimmel and free the dragons he has captured. But, Hiccup and Toothless realize that the dragons will always be in danger from humans, and they bid farewell as all the dragons head off to their new home in the Hidden World. 

For How to Train Your Dragon: The Hidden World, Dean DeBlois returns as director, with Brad Lewis (Ratatouille, Antz) and Bonnie Arnold (How to Train Your Dragon 1 and 2, Toy Story, Tarzan) producing. The film was released by Universal Pictures.

Also returning are many of the hero characters from the previous films, including Hiccup (Jay Baruchel), Astrid (America Ferrera), Hiccup’s mom Valka (Cate Blanchett), Snotlout (Jonah Hill), twins Ruffnut (Kristen Wig) and Tuffnut (Justin Rupple), Fishlegs (Christopher Mintz-Plasse), Gobber (Craig Ferguson), and Eret (Kit Harington). New to the series is the evil Grimmel (F. Murray Abraham). 

With the exception of Valka, the animators were able to reuse the existing human models for this third installment, although the hair and surfacing were updated, according to David Walvoord, visual effects supervisor. “We really weren’t happy with Valka. We wanted to make her more appealing,” he says. “She was incredibly difficult to light, and whenever something is hard to light, it’s generally a clue that you can do better. So we took another shot at her. And from a story point, that was really important. We were distancing her a bit from that unredeemable act of abandoning her child (Hiccup) in the previous films.”

In this film, the Vikings of Berk are outfitted with dragon armor made from fallen dragon scales. Initially, this was conceived just for Hiccup, for a particular scene – the premise being that the armor was fireproof and would enable the character to walk through fire. But once the artists dressed Hiccup in the armor, “it became obvious that it was really cool, and we all responded strongly to it,” Walvoord notes. “And then we realized the film was missing a unique visual statement in terms of the characters. For the environments, there was the Hidden World and New Berk. But the characters felt like a continuation [of the second movie], since not a lot of time had gone by – just one year in the film.”

Soon, the team was pointing out more scenes in which Hiccup could wear the armor. And then production designer Pierre-Olivier Vincent suggested that all the dragon riders should wear the armor. Everyone loved the idea. “We had done different costumes for them, but it was kind of more of the same,” Walvoord says. “And then we saw that dragon armor…. It really does make the characters look fresh and different from the previous movies.”

The addition of the dragon armor was particularly difficult for the modelers, who had to hand place all the tiles and fit them together like they were solving a jigsaw puzzle – 3,620 discarded scales from Toothless alone comprised Hiccup’s body armor.

The artists also reused the returning hero dragon models, which were also refreshed and resurfaced. 

The crew certainly had experience in dragonology from the first two films – modeling and animating wings and tails of all shapes and sizes. And in some cases, multiple appendages. Also, multiple dragons. But in The Hidden World, they had to model and animate more than few dragons (close to 65,000 in all), with different looks, different flying styles, different gaits, and different ways of spewing fire. In the first film, the group was limited to no more than eight dragons in a single shot or the system could crash. Here, in a shot within the Hidden World, the team pushed that to approximately 42,000 dragons. 

In the previous films, we were introduced to a wide variety of dragons, including Deadly Nadders, Gronckles, Rumblehorns, Hideous Zipplebacks, Terrible Terrors, and more. Joining them for this release are four new types of dragons: the Deathgripper, the Hobglobber, the Goregutter, and, of course, the white Fury. One of the more difficult dragons to animate was the Deathgripper, which has a claw-like leg, resulting in an unusual gait. It and the other characters were animated using the studio’s Premo software. But, the most technically challenging dragon overall was Light Fury.

All that Glitters

All-black and all-white characters are notoriously difficult when it comes to animation because detail is often lost in the dark, monocolored coat, while it is accentuated in the white coat. In The Hidden World, we have the return of the lead dragon, the all-black Toothless, along with the new all-white Light Fury. “We struggled to make her look appealing. We found that if we put too much detail into her, she went lizard very quickly,” says Walvoord. “If we had too little detail, then she didn’t match Toothless. So, we played with a lot of patterning. We eventually hit upon this idea of shimmer, like you see in eye makeup, to give her this glittery quality.” 

But on the dragon, adding glitter on her eyes didn’t quite work like it might on a human. “It looked like we were trying too hard,” Walvoord adds. “It looked like she was wearing a lot of makeup. It was a bit over the top and not very appealing.”

Instead, the group added a subtle stripe pattern – one that Toothless has as well but is much more subtle. Then they reinforced that stripe pattern with the shimmer, which provided a strong visual level of detail that could be downplayed easily in close-ups. “In fact, visually, when Light Fury is really close to the camera, you see glitter but not the stripes. But then as she recedes farther away, suddenly you can see how all those bits of glitter reinforce the stripes, and they turn into a stripe pattern,” Walvoord explains. “It really helped us balance how much detail is appropriate. We can make her soft in close-ups, but then have more visual interest when [she is] farther away and sitting next to Toothless.”

Animating Light Fury was just as challenging as finding the desired aesthetic. “Obviously, she is an important character, and we had to find a way to make her look wild. But at the same time, she had to be incredibly charming and appealing, with a little bit – well, with a lot – of attitude,” says Walvoord. “She had a lot of dimensions to her personality, and it took us a while to find them.”

When the audience is first introduced to Light Fury, she is used as bait by Grimmel in his attempt to capture Toothless. She is stunningly beautiful. “Toothless is conflicted by loyalty, but he’s drawn to what is so natural,” says DeBlois. “For him, that’s embodied by the Light Fury; she offers an innocent existence untainted by humans.”

But, Hiccup and Toothless are a team, and have been throughout the series. So, this third wheel that is coming between them had to be both likeable and spectacular, says DeBlois. The dragons do not speak, so the animators had to be sure the animation spoke for them. 

All the dragons exhibit some type of animal influence in their personalities and the way they move. For Stormfly, a chicken; Cloudjumper, an owl. For Toothless, that ranged from horses, to dogs and other domesticated animals. Since Light Fury is a variant of Toothless’ species, there had to be similarities, and the animators leaned toward big cats to exude confidence, elegance, and aggression. Just nothing too anthropomorphic. 

“You’re 100 percent reliant on the glance, posture, eyes, and reaction in the body,” says DeBlois. 

The Hidden World

As far as the environments, there are a few new locations in this installment, but the most impressive, by far, is the Hidden World of the Caldera – an expansive, wondrous home to dragons accessed through an underground volcano. It comprises a network of chambers and tunnels that wrap around the Earth, with cascading waterfalls and glowing foliage. 

In designing this unique world, the artists referenced nature. Walvoord points to a cave in Mexico that had been flooded for many years; when it was drained, there were huge crystals that had formed. “It was a foreign-looking landscape that existed underground,” he says. “And that became the basis for our Hidden World.”

As Walvoord points out, there are lots of huge crystals at odd angles spaced throughout the world that form pillars, around which the rest of the world is built. The crystals serve a dual purpose: as a design element and a practical element (a light source that illuminates the space). “It was important to Dean [DeBlois] that this feel like we’re underground. And yet, we couldn’t make it feel like a cave, that the dragons just live in this rock in the ground. It needed to feel natural, amazing – as if they were living above ground.”

In addition to the crystals, the artists decorated the space with elements that do not need a lot of light, such as corals and mushrooms, and then combined them in unexpected ways to turn this into a “completely foreign-looking landscape,” Walvoord says. “But at the same time, it is completely grounded in what actually exists in the real world.”


On the tech side, DreamWorks’ new MoonRay renderer had the greatest impact across this film, turning the Hidden World into an enchanting paradise andfilling the shots with thousands of unique dragons. 

For far too long, says DeBlois, lighting has been the bottleneck that restricted the ambition of

animated films. “Now, we have a powerful tool at the back end that allows us to deliver on the promise of huge worlds full of lush, beautiful settings and many more fully formed characters than we’ve ever been able to render,” he notes. “What once required starting anew every time a shot was delivered, is now significantly streamlined. It’s astonishing what it has freed us up to do.”

MoonRay, a ray tracer, is a physical-based renderer (PBR) that calculates light and shadows as they are in the real world, making details sharper than ever. It replaces the studio’s previous renderer, MoonLight, a scan-line renderer that used a point-based global illumination system. 

As Walvoord points out, just because someone is using a ray tracer doesn’t mean they are doing physically-based rendering. There are many animated movies that do not. “It was clear that for us, it was a good choice,” he says. However, the results were not immediate. “When we started working with MoonRay, we weren’t satisfied with the images we were getting. It kind of felt like we were doing more of the same with a better renderer.” So, the group began working closely with R&D to understand why that was happening. 

“The shader guys convinced me that the problem was we were not using PBR,” Walvoord adds. “So, it meant we had to redo our film.” But, the results were well worth the effort. 

“You build this physically-based library of shaders that the surfacers use, rather than just artistically doing it, which is how we’ve always done it in the past,” says Walvoord. “It elevated everything. Suddenly, everything responded to light better, and it was more consistent when lit.”

Walvoord is clear: The Hidden World could never have been done with the studio’s previous renderer. As he explains, the lush, green oasis in How to Train Your Dragon 2 was made using three different sets and numerous matte paintings, so it could only be shot from three points. “That was all the complexity we could handle,” says Walvoord. “The Hidden World was different because the production designer very early on made the case that we had to sell the journey through that world so the audience understands how expansive it is; that is how we were going to sell the ending [of the film] to the audience.”

A good amount of time is spent on this voyage through the world, as the pace slows while Astrid, Hiccup, and the audience gaze at this wondrous natural world, passing through, among other things, a luminescent mushroom forest. 

“But instead of the scene being 90 percent digimatte as it was in Dragon 2, it’s only about 20 percent digimatte, and that’s for the far, far background,” Walvoord says. “We’ve got some ridiculous numbers we collected. We built it using 68 million mushrooms and 79 million pieces of coral. There’s 140 million little plants growing everywhere. We have something like 3,000 waterfalls in there, and 6,700 rock spires. It’s orders of magnitude beyond what we had done before.”

Walvoord points out that despite using the new renderer, the Hidden World still posed a rendering challenge due to all the elements and the effects integration, as well as the crowds. Ray tracers, after all, are built to use a limited number of light sources to do the job well. Any time there are mini light sources like the team had here, there is a lot of noise. It was a creative challenge as well. “The mushroom forest is basically self-illuminated with the bioluminescence. The whole thing is incredibly colorful, and there’s a lot of detail. It’s overwhelming,” he says. “So, figuring out the concept of how the light traveled and the directionality of it, and organizing that information, took quite a while.”

Despite the amount of work that went into designing and building this environment, only about six minutes of the film takes place here. In comparison, that accounted for 69 percent of all the rendering that went into DreamWorks’s 2016 film Trolls. “It set a new record for us,” he says, noting the total rendering time for the Hidden World was 131.3 million core hours!

But MoonRay’s capabilities do not stop there. The film’s environments are larger than what DreamWorks has tackled before, contends Walvoord. “MoonRay grants us the ability to put everything we want into our world,” he says. One such example takes place in the Hall of Berk, where Hiccup and Astrid rally their people. Here, there are nearly 200 characters dining together, many sporting beards or wearing fur – elements that require a great deal of computational resources. In this one scene alone, there are more than 150 mugs, 200 spoons and bowls, 350 apples, 10,000 rocks, and 60,000 strands of hay. In addition, the camera is following a group of main characters walking through the crowd. This means that any member of the crowd that appears close-up with the main characters must be portrayed in the highest detail. “Cheating” with lower-quality versions of the characters just wasn’t possible.

And, the devil was certainly in the details on this film. There are 2,000 unique character pieces in the Hidden World, including hair, clothing, and accessories. In the village of Berk, the blacksmith shop alone contains 1,097 unique props and assets. There are even 756 nails in Hiccup’s house. Details that would not have been possible before.

Integrating PBR also gave the group the pathway to redo the characters, particularly the skin. More detail was needed, so they decided to add pores –  which had always been taboo in animated films. “We had been getting better translucency and specularity. So, we added pores, stylized, not photoreal, which added more detail in the specular breakup,” notes Walvoord.

Then the grooming artist working on Hiccup and Astrid brought up the notion of adding peach fuzz, to make the models look more sophisticated. “Now, if you look closely at Astrid, she is covered in peach fuzz – her nose, ears, face… everything is covered in really thin hair that’s fairly translucent, in a very subtle way,” says Walvoord.

As a result, these changes naturally softened the characters. “We were amazed. The lights worked better. Everything was just working better,” Walvoord adds. “There’s now a lot more sophistication to Hiccup and Astrid, but they still fit the style of our movie.”

Perhaps more amazing is that the crew made this significant conceptual, look, and workflow change – where they began working with the ray tracer and then implementing the switch to PBR and redefining the look of the film – in a mere six weeks. And then they had to redo the characters created with the previous method.   

Effecting Change

Although expensive, MoonRay also enabled the effects artists – and others – to play with fire, literally. In the film, the DreamWorks artists created photoreal fire for the first time, and there is a good amount of it – from the dragons belching fire, to the scenes throughout Berk and New Berk that are lit by candles, torches, dragon fire – even a chandelier of fire. Before MoonRay, the artists created a fire effect using red, yellow, and orange lighting, since otherwise would have been too complicated and time-consuming. But that changed with MoonRay.

“You can change your mind. You can try new things. You can explore. The speed has truly opened up a whole new universe for us,” says Pablo Valle, head of lighting.

Now, the visual effects department still starts the process by creating the simulation, but then the lighting team brings the image to life. The result is a photorealistic fire that bounces and flickers as it would in real life. 

In the past, fire (and clouds) were not only simulated, but also lit by the effects department, not by lighting. For this film, effects still handled the more complex work, but lighting dug in as well for the less complicated shots, improving the workflow and enabling more collaboration among the departments. “Even some of our atmospherics were constructed in lighting because effects provided a library, and they could plug those elements together,” says Walvoord. “It made a big difference having a single person being able to own the lighting for all the elements in a shot, rather than having it spread across multiple people. It was a win-win, and the effects team was happy to pass the task on to lighting, and the lighters were dying to light it all.”

As a result, fire also became light sources, such as when Hiccup and Toothless walk through fire at the beginning of the film. “It’s reflective and illuminating correctly,” Walvoord points out.

In addition to fire, there is a good deal of water simulation in the film. There are a lot of waterfalls, and a unique process devised by an effects developer allows an effects artist or digimatte artist to “paint” in waterfalls wherever they’d like in a scene. “It’s amazing to see this work; you can put in rocks and the water will bounce off the rocks,” Walvoord says. 

By turning what is usually a very complicated water simulation into a library element, the crew was able to expand the number of waterfalls in the film. Alas, this process did not work on the hero waterfalls; those still had to be done traditionally. And that includes the biggest water sim in the film – and the biggest that DreamWorks has tackled to date –  which is the caldera at the entrance to the Hidden World, which sits below the surface of the ocean and water constantly pours into it.

Friends for Life

The Hidden World is a coming-of-age tale, the final piece in the trilogy, which follows the main characters as they evolve and mature: Hiccup from the tentative, shy adolescent, and Toothless from a cute pet, into a pair of constant companions who bolster each’s confidence as they become leaders of their species. And then, to encouraging each other to follow their hearts, even though it leads them in separate directions.  

And Toothless is not the only one who falls in love. Hiccup also finds love, with someone who has supported him all along, just as Toothless has: Astrid.  

While different worlds now separate Hiccup and Toothless, they are never far from each other’s heart, as they are truly friends for life.

Karen Moltenbrey is the chief editor of Computer Graphics World.