Dating back to the late 1800s, visual effects have long fooled film and television audiences. Modern filmmakers and VFX engineers have since taken the industry to new heights, with the Game of Thrones franchise breaking new ground with its digital implementation of three lifelike dragons. The intensive dragon-engineering process spanned a number of disciplines, drawing inspiration from the natural world and human engineering. Each aspect of the dragons, including their physical appearance, flight mechanics, and expression of emotion, had to be meticulously perfected through a rigorous development process. This work ultimately raised the technical bar for the television and film industries, while also proving invaluable for several other industries that utilize VFX technology.
As children, we loved to fantasize about living in a world with dragons, mermaids, and unicorns. But as we grew older, we all had to eventually face the harsh realization that these creatures can only exist in our imaginations. This is probably a good thing, as we can all agree that a world with dragons flying around burning down cities is terrifying. However, we all still have remnants of that youthful curiosity for fantasy. While we’ll unfortunately never be able to witness a real-life dragon, advancements in visual effects have enabled us to experience shockingly realistic depictions of these creatures on screen. The Game of Thrones (GoT) television series, created in 2011 by David Benioff and D. B. Weiss, presents arguably the most lifelike on-screen portrayal of fantasy creatures to date. Game of Thrones, with its uniquely massive scale and substantial production budget, blurred the lines between fantasy and reality and pushed the limits of television production. Among the show’s many groundbreaking feats, the show’s crowning accomplishment is arguably the creation of three terrifyingly lifelike dragons — Drogon, Rhaegal, and Viserion — that wreak havoc on the enemies of Daenerys Targaryen, the Mother of Dragons.
Creating these dragons was an incredibly intensive VFX endeavor, with a single dragon scene requiring six months of work from a team of ten people. It was a technical, comprehensive, and highly sophisticated process that the show’s engineers, fueled by caffeine and sheer passion, perfected on the fly . The tight time frame for production forced the team to adopt an agile methodology that could efficiently adapt to last-minute changes or setbacks. Beginning with simple sketching and blueprinting and progressing to digital 3D modeling and object rendering, the engineering process utilized elements of lizard and bird anatomy, airplane engineering, and flamethrowers, among many other things, to bring the dragons to life . Ultimately, the obsessive attention to detail and cutting-edge technological creativity that went into Game of Thrones and its dragons set a new gold standard for visual effects and sent a ripple through not only the entertainment industry but industries like medicine and military that utilize visual effects.
Figure 1: Game of Thrones’ dragons in their fully-grown form. 
A Brief History of Visual Effects
The first documented use of visual effects in motion pictures came earlier than many might expect, dating all the way back to 1895, when filmmaker Alfred Clark invented the “stop trick” . Attempting to film a reenactment of the beheading of Mary, Queen of Scots, Clark had Mary’s actress step into the execution block before having the executioner’s actor swing the ax. Just before the ax reached Mary’s neck, Clark stopped filming and instructed the actors to freeze. He then positioned a dummy in the place of Mary’s actress and resumed filming, with the executioner’s ax coming down to sever the dummy’s head. Clark then stitched the two shots together, creating a seamless continuation that provided the illusion of a real beheading. In the decades following Clark’s revelation, visual effects technology progressed at a slow but steady pace, with filmmakers relying on a handful of rudimentary tricks like double exposure, rear projection, and green screens to captivate audiences .
However, in the 1980s, the world of visual effects was turned on its head with the advent of modern computers and computer-generated imagery . These advancements completely revolutionized the film industry, enabling filmmakers to explore the outer reaches of their imagination and bring their most ambitious projects to life. Novel techniques like motion capture, reflection mapping, and inverse kinematics produced incredibly immersive and photorealistic scenes that often bordered on being indistinguishable from real life. This era of growth continued into the subsequent decades, bringing about a number of landmark films that remain staples in our cultural lexicon, including Star Wars, Back to the Future, Jurassic Park, and Toy Story . VFX engineers and artists have since continued to push boundaries and build upon prior advancements, culminating in the modern-day entertainment landscape in which the majority of TV shows and box-office movies rely heavily on VFX and computer-based graphics technology.
Figure 2: 3D model of a CGI dinosaur used in production for Jurassic Park (left) , frame from Jurassic Park depicting finished product of a CGI dinosaur (right). 
Dragon-Building 101: An Overview of the Process
Before Daenerys Targaryen’s dragons soared over the skies of Westeros, they began simply as an idea from a group of ambitious show-makers. The show’s producers had a clear objective: to create three on-screen dragons that look, move, and behave like a real dragon would. It was vital that the biomechanics and aesthetics of the dragons resembled actual animals, as they didn’t want the dragons to appear robotic or artificial but also wanted to avoid humanizing the dragons . The team had a few reference points that guided the design process: the dragons’ skin was to resemble a crocodile, their wings were to resemble a bat, their scales were to resemble a sungazer lizard, their neck vertebrae was to resemble a tyrannosaurus rex, and their ribcage was to resemble a bird .
Dan Katcher, a veteran character designer with experience building dragons and other creatures, was selected to lead the dragon-making process and later received an Emmy for his work on the show . His first step was creating basic sketches of the dragons to get a preliminary idea of how they would look. Next, he had to build detailed 3D models of the dragons, including proper proportions and external appearance. Most of this work was done using a digital modeling tool called ZBrush. Katcher used objects called ZSpheres (portrayed in Figure 3), which are an advanced digital sculpting tool for organic character models, to build out the basic proportional infrastructure . Doing so, he created essentially a stick-figure version of the dragons that could then be “skinned” (covered in a mesh resembling a skin layer) for further modeling. Next, he had to build out the full skeletal and muscular structure bone-by-bone and muscle-by-muscle, which was necessary to ensure that the dragons’ movements resembled those of real, living animals. Once the basic proportions and internals of the dragons were modeled, he then had to meticulously craft the scales, horns, frills, and claws that make up their external appearance. He opted to design each scale individually to eliminate the possibility of the dragons appearing artificial.
Figure 3: Dragon model using ZSpheres before (top) and after (bottom) skinning. 
Once the 3D models were complete, Katcher then sent the files to VFX engineers who used advanced graphics programs like Maya and 3D Studio Max (depicted in Figure 4) to seamlessly integrate the dragons into actual show footage. To accomplish this, engineers fed the dragons through a number of stages of cumulative development . The animation stage utilized mathematical modeling to map the dragons’ movement and add texture to the outer layer of the dragons. The simulation and FX stage seamlessly integrated simulated elements like destruction, smoke, fire, or liquids. The lighting and rendering stage utilized precise digital lighting to ensure that the light color, shadows, and intensity matched with the originally shot footage. The compositing stage combined all aspects of the film by layering the elements on top of each other, utilizing techniques like color correction and masking. At this point, the dragons were finally ready to grace the screens of millions of mesmerized viewers across the world. While Katcher spearheaded the entire process, it was far from a one-man-job. In total, over 300 designers and engineers across a multitude of VFX studios were enlisted to complete the task, culminating in one of the most ambitious and technically-complex achievements in the history of television.
Figure 4: Maya 3D model of Daenerys Targaryen and dragon, including accurate texturing and lighting. 
It’s a Bird! It’s a Plane! It’s a … Dragon?: Engineering Flight Mechanics
The flight mechanics of GoT’s dragons incorporate aspects from both the natural world and the world of engineering. To get a basic idea of the anatomy of winged creatures, the producers began by playing around with store-bought chickens on the studio’s kitchen table . They cut open and took apart the chickens, examining the muscles, tendons, ligaments, and bones that allow wings to move. Specifically, they observed the birds’ breast muscles and connective ligaments, along with the three joints (shoulder, elbow, and wrist) that allow wings to function . They then delved deeper by thoroughly researching the skeletal structures of various flying animals, with eagles and bats being prominently featured . They wanted to uncover the intricacies of flight through a biological lens, including which specific structures make for efficient and graceful flight. They discovered that a broad chest, including a pronounced keel bone and an elongated sternum, provides space for powerful muscles to drive flight and that a flexible wing structure increases maneuverability in the air, which they incorporated into the dragons’ design.
Figure 5: Skeleton of an eagle, which was an important reference point in designing the dragons 
Although nature provides ample material to study the mechanics of flight, a challenge faced by designers was the sheer size of the dragons. There simply doesn’t exist a flying creature in nature that comes close to the size of GoT’s dragons, which forced designers to look for alternative sources of inspiration. They settled on the Boeing 747 as a point of reference, with the iconic airliner being approximately the same size as a fully-grown dragon . They wanted to discover the engineering principles that allow such an enormous object to soar through the sky with such grace. This research shed light on the principles of fluid dynamics that make flight possible, including generating lift and reducing drag. Specific features that are crucial to the performance of the Boeing 747 include raked wingtips to mitigate drag, fly-by-wire spoilers, outboard ailerons to reduce weight, and wings with a high sweep angle for efficient cruising . All of these features were studied, analyzed, and integrated in some way when creating the dragons, resulting in creatures that glide and maneuver through the air like modern airliners.
Dragons Have Feelings Too: Communicating Emotion
GoT’s dragons are complex creatures with a range of emotions and mental states. Whether expressing love for their mother or hatred for their enemies, being able to effectively communicate emotion was a crucial requirement for the dragons. However, the team wanted their interactions to be realistic and wanted to avoid humanizing the dragons in the process. Thus, they had to carefully walk the line between expressivity and mechanicalness.
They accomplished this by using specific features and body language cues as conduits for emotional expression . The dragons’ eyes, facial features, and other body parts work in unison to articulate specific emotions, similar to the ways that household pets like dogs or cats communicate feelings to their owners. When the dragons are happy, their eyes are radiant and open, their faces are relaxed, and their scales are bright and luminous. When the dragons are sad or in pain, their eyes are squinty and small, their faces are tight, and their scales are drabber and more translucent. When the dragons are angry, their eyes are sharp and their faces are intense. They also have frills on their neck that rise in times of anger, a feature that was inspired by the frilled lizard.
These variations were accomplished by incorporating around a dozen facial muscles into the dragons’ models, each with a unique role in the expression of emotion. Based on facial muscles found in dogs (displayed in Figure 6), specific muscles in the dragons involved in facial expression in the eye region include the frontalis, the orbicularis occuli, the retractor anguli occuli lateralis, and the levator anguli occuli medialis. Muscles involved in expression in the nose/mouth region include the zygomaticus, the buccinator, and the levator nasolabialis. These muscles work independently to simultaneously contract in times of discomfort or expand in times of comfort, which signals to humans, or other dragons, their state of mind. Additionally, specific craniofacial structures and pieces of cartilage present in frilled lizards were incorporated into the dragons to give them the ability to raise their neck frills, giving an increased intensity to their anger response.
Figure 6: Muscular structure in the faces of dogs. 
The designers even went as far as giving the dragons twitching eyes, labored breathing, less fat, and visible rib cages in scenes in which they were starving or ill . These are based on fundamental responses like tensing muscles, burning fat reserves, and consuming muscle tissues that mammals’ and reptiles’ bodies take to conserve energy and maintain organ function in times of starvation, severe illness, or other ailment. These variations combined to give the dragons a wide range of emotional expressivity that allowed the show’s producers to convey the subtleties of their interactions with their mother and other characters. This added another layer of complexity to the dragons, elevating them from merely visually-stunning creatures to genuinely sensitive and demonstrative individuals with their own unique character development throughout the show’s story arc.
Figure 7: Dragon in a famished state, indicated by fatigued eyes along with decreased radiance and increased translucence in the skin. 
Conclusion and Impact
Game of Thrones’ complexity, ambition, and sheer enormity is unlike anything we’ve seen on screen, blowing the top off of what we once considered possible for television from both a technical and storytelling perspective. By the show’s later seasons, each episode required an unthinkable budget of around $10 million . So where did all that money go? A significant portion was allocated to visual and special effects, with each VFX shot requiring meticulous multi-stage editing and processing to achieve seamless digital integration. The most rigorous aspect of this process was creating from scratch three computer-generated dragons that soar through the sky and rain fire on anyone who stands in their way. The dragons contributed heavily to the show’s lightning-in-a-bottle success, creating a tangible “Game of Thrones effect” across the television industry. Other production companies like Netflix and Amazon have since poured immense funding into advanced VFX ventures for their TV shows, hoping to recreate the magic that has elevated Game of Thrones to cultural immortality.
But GoT’s impact transcends the television industry, with the boundaries it broke in VFX allowing a number of other industries to reap the benefits. For instance, the biomedical industry has long used visualization technology to make complex concepts accessible . Whether used in creating documentaries and informative videos or building imaging technologies for use in clinical analysis and diagnosis, being able to display detailed computer-generated representations of biological structures is invaluable to a rapidly advancing industry. Initiatives like the Visible Human Project and the 3D Embryo project aim to bridge the gap between VFX and medical imaging to enhance our understanding of human and cellular biology . In rigorously adhering to principles of biology throughout the dragon-building process, Game of Thrones engineers’ efforts have been pivotal in our journey to map biological structures in three-dimensional space using computer graphics.
The military, on a similar note, has utilized VFX-based technologies like AGOGFX to create photorealistic digital live training scenarios that simulate explosions, gunfire, nuclear threats, and other battlefield situations . The digitally-generated explosions, fire-breathing, and general destruction caused by GoT’s dragons has provided important source material for inspiration and integration in these state-of-the-art military training technologies. What began as an ambitious idea among a group of steadfast show-makers to create three Boeing 747-sized dragons that spit fire and decimate cities has evolved into something that has had a genuine progressive impact in a number of key scientific and public-good pursuits.
Figure 8: 3D visualization of DNA double helix built using modern VFX technology. 
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