Source: UniversalTo create the most complex sequences in The Mummy: Tomb of the Dragon Emperor, a seamless blend of visual and mechanical artistry would be required. With an amazing range of effects—from ancient creatures and avalanches to intricate battle sequences with massive numbers of digital characters in digital environments and practical effects—the filmmakers had an enormous task at hand.
Accomplished VFX producer Ginger Theisen headed the visual effects department. For the large number of VFX shots required, more than 800 at last count, Theisen brought on two digital houses: Digital Domain, headed by VFX supervisors MATT BUTLER and JOEL HYNEK, and Rhythm & Hues, headed by VFX producer DEREK SPEARS.
The SFX department was led by industry veteran SFX supervisor R. Bruce Steinheimer. In order to develop the large number of mechanical effects for the film, he oversaw four different SFX shops in Montreal and China. Says Steinheimer, "We had over 100 people working in effects on different continents at the same time in order to make sure all the effects would be ready for both the main and the action units." Steinheimer was tasked with creating mechanical effects that would blend into digital extensions of CG creatures. In the Shanghai chase sequence, for example, the chariot needed to interact with its surroundings as if it was being pulled by real horses. He explains, "We put a plow on the front of it so we could crash into things, because the Terracotta Emperor and the bronze horses are in the digital realm. As the part of the chariot, they are on separates and start to spin out of control, so we used a hydraulic spin rig that travels down a track to create that effect. It ejects the sarcophagus, which slides through the streets, causing mayhem and destruction."
After the shots of the chariot crashing through buildings were completed, a plastic horse was attached to the front of the chariot to give reference for the performers when they filmed. "This gave our actors something to ride on," explains VFX producer Spears. "We replaced the plastic horse with our CG bronze horse later."
"All the horses were, originally, very heavy bronze statues built by the ancient Chinese," explains animation director CRAIG TALMY. "When they buried their dead emperor, they adorned his burial place with regal statues of horses." After Alex O’Connell accidentally lifts the curse, the horses "come alive." "We had to make them look like real horses," continues Talmy, "with their weight, structure and underlying bones and musculature. At the same time, they’re made of bronze, so they have to move in a way that suggests hollow metal about an inch thick."
Raising the Emperor Mummy
For the Emperor Mummy and his legion of Terracotta Warriors, the effects team developed a series of "liquid solid" warriors made of clay, who were able to flex and bend at will. Whenever they move, they crack and reform.
In order to begin work on the character of the Emperor Mummy, a cyberscan was performed on Jet Li using multiple three-dimensional cameras; a submillimeter threedimensional model of his entire body was created. Digital Domain motion captioned his entire body, then "staccatoed it" to infuse the characteristics of a terracotta statue. Cohen expands upon the process: "Instead of using makeup, we created a threedimensional image of Jet Li’s face by taking very complex measurements of his face while he acted the part. Then, we made a CG image of him that can talk, which is the essence of the real actor. We wrote in new algorithms to describe geometries which fracture and reform. So, every time he speaks, it fractures; it is constantly breaking and reforming."
As the Emperor has control over all of the elements (earth, fire, air, water and wood), he is quite a dangerous foe. To add insult to injury, he possesses off-the-chart healing powers. Explains Joel Hynek, co-VFX supervisor at Digital Domain: "He is filled with magma, so when he cracks, pieces fall off; the magma comes to the surface and rapidly solidifies—and he becomes the replenished terracotta-statue emperor."
The trick for the VFX team was to give the Emperor movement without making him look as if he was a human wearing a rubber mask. Digital Domain had some science experiments of its own as they performed stress studies on terracotta. They wanted to know what it looked like when it was expanded, cracked and crushed, and incorporated the results into the look of the mummy and his legion of doom. Hynek elaborates, "The Terracotta Warriors don’t heal unless they can get across the wall; they will continually deteriorate. However, if they can cross the wall, they become immortal."
Crafting Legions of Warriors
Though only a fraction of the Terracotta Warriors have been excavated from the depths of Chinese soil, the production was tasked with bringing them all back to life. Digital Domain was responsible for the creation of the vast armies of both the Terracotta Warriors (the Emperor’s men) and the Foundation Army (those killed by the Emperor).
They had to render a total of 2,500 Foundation Soldiers and 4,800 Terracotta Warriors. "The Foundation Army are the good guys," explains co-VFX supervisor Butler. "These are the workers that have been incarcerated under the Great Wall of China for a couple of thousand years. They come to life as desiccated beings that have a really spooky look. We didn’t just build them as skeletons, but in a multitude of degraded states—from ‘healthy guys’ to complete ‘bone men.’ It was tough, actually, because it was hard to depict a desiccated being as having a good character."
By examining reference materials from ancient embalming imagery to often macabre books on anatomy and physiology, the team became quick studies on kinesiology and musculature. "Using the research material," explains Butler, "we built a set of tools that enabled us to take a body from an undamaged-but-aged form down to muscles, tendons and sinew—in their decayed form—down to bare bones."
In order to give each character independent movement, Digital Domain used a program called MASSIVE, developed by Stephen Regelous and used for battle scenes for multiple films—including those of The Lord of the Rings trilogy. "Stephen designed and created a tool set that allows you to render thousands of sentient beings, whether they are humans or creatures," explains Butler. "They all have their own individual decision making capabilities. He refers to these individual characters as ‘agents.’ Each agent has the capability of making his own decision, based on rule sets designed by the artist. So the artist is literally designing the brain."
The original Terracotta Warriors provided their own reference, as each of the Xi’an Warriors was crafted with a unique face, hairstyle and body type. After scanning images of them, the team devised cunning ways to swap and exchange body parts, so the audience never sees two of the same soldier as they roar across a battlefield. When a geometric library of warriors were married with an assortment of terracotta textures, lighting, shade and movement helped to render thousands of unique soldiers.
Now, the team just needed to provide motion to the warriors, while they broke apart again and again. Not an easy task, because they had to take inanimate objects and build motion and fighting movements into their repertoire of behaviors. "Before we did anything, we did a Battle Action Reference Shoot," explains Hynek. "Vic Armstrong, Matt Butler and I started working with different battle actions, then Matt and Vic worked in Montreal to capture what we needed."
"It was important to Rob that the warriors look real and not just like replicated figures," explains Armstrong. "They are very grandiose, epic-style battles and, luckily, 21st-century technology is a big help. I worked closely with the VFX guys to plot every shot. I did a lot of motion-capture work with a mixture of live people to represent the two armies—blue suits for the Terracotta Warriors and green suits for the Foundation Army. They are actually fighting, so it looks realistic. The computer took the physical movement of a real person and replaced it with the CG terracotta and skeletal figures. The staging of the fight is also important. It has to have enough humor to release the tension, but, at the same time, it has to look violent and realistic."
Building New Creatures
In addition to his incarnation of the Terracotta Emperor, Jet Li’s character also has the ability to morph into other forms, specifically a three-headed gorgon that is derived from a mixture of Western and Chinese mythology. Image Matrix projected Li’s performance onto the CG creature that spits fire, snatches a victim and flies away. "The Emperor chose his first incarnation to be a 30-foot, three-headed gorgon," explains Rhythm & Hues’ digital supervisor BOB MERCIER, "so we had to decide how much the face should look like Jet Li and how much it should look like the head of a reptile. It needed to have the spirit of Jet, yet the Mummy character should somehow come through as snakelike, but with a soul underneath. It was our goal to give an Asian influence to the gorgon’s face. You can see a ghost of Jet Li there, but it still works as a creature."
Another incarnation of the Emperor is the Nian, a half-lion/half-dog creature based on the Foo Dog, a temple guardian of ancient China. Shares Cohen, "We’ve taken it into a much more extreme bestial concept; it is a very large creature about nine-feet high who can grab a plane right out of the skies. Jet’s character is a shape-shifter, and this is one of the different creatures he can become."
For each creature, Rhythm & Hues produced a 3-D computer-generated model, which shows muscle tone and skin texture. This was sent to the filmmakers for their input. "Once the model was agreed on by everyone, we moved forward and began the animation," explains animation director Talmy. "We send it down the pipeline to the rigging department—the people who populate the models with all the mechanics to allow them to not just move, but move in the way we want them to."
As no one has seen a Yeti up close and lived to tell the story, the characters were computer generated and the VFX team was given free reign in the designing the brutes. "The Yeti have always been a favorite part of the movie for the filmmakers," states producer Daniel. We’ve always thought it was just really cool to have the Yeti and Shangri-la be a part of this movie. The Yeti are other creatures, like the Mummy, that people from all cultures can relate to."
Cohen wanted his abominable snowmen to have unique personalities. With no dialogue for the Yeti (save roars and grunts), the animation team needed to convey everything through body language. Laughs Talmy, "We had to find a way to pump character performances into a scene where all that’s required of our character is that he run down a hill and smash a guy in the face."
The Yeti were originally designed to be a cross between a man, polar bear and snow leopard. Over time, the animators moved the design closer to that of a man. They liked the fact that the creature—when obeying the enigmatic Lin—could pick up an enemy, give him a razor-sharp look of disdain, then toss him into the frozen wilderness.
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