Enhancing the Animated Movie-goers Experience with the Science of Gas Dynamics
Angelia Romero
Intro to Physical Science
Professor Paquette

Enhancing the Animated Movie-goers Experience with the Science of Gas Dynamics

The goal of animated films has been immerse the audience in a fantasy world while maintaining some semblance of reality in those worlds. Various techniques are used to generate motion picture animation but they have all taken advantage of a phenomenon called “persistence of vision”. The “persistence of vision” is where the brain reads a rapid series of images as an unbroken movement. From the beginning, the animation was achieved by filming thousands and thousands of still images that were edited together to produce one continuous reel of film. Teams of artists meticulously drew each frame were tasked with capturing the aesthetic of the film while also mimicking the physics of the real world. Animation where each frame or cell is hand drawn and then compiled is called traditional or classical animation. Snow White and the Seven Dwarfs, generally considered the first full length animated feature using tradition animation, required 1,500,000 hand-drawn and colored frames to make the movie. As computing technology grew less expensive, movie studios like Disney gradually transitioned from the millions of hand paintings to computer based animation. Pixar finally broke the mold for animated films by releasing the world’s first computer animated feature film with Toy Story in 1995. Since 1995, movie studios have been pushing the boundaries for physical processes and special effects that can be captured in an animated feature. This paper will concentrate on some of the physical processes that animators, designers and computer programmers are tasked with modeling. The hottest areas under investigation to create better and more realistic animated worlds are modeling of thermal and physical processes of gas dynamics like smoke, dust and cloud formation. The effects of gas related phenomena are an important part of our real world. These effects are an integral part of enhancing a viewer’s experience when watching an animated film. Pressure, density, temperature and concentration are all important quantities that animators have to keep track of to properly model fog, steam or smoke. The behavior of smoke may be something we take for granted when viewing it on film but the flow of a plume of smoke is a very complicated process to model mathematically. A computer model producing realistic smoke must take into account thousands of variables and initial conditions to simulate the process from the initial stream to the swirling vortices as the smoke dissipates. A particular advance in gas modeling simulations was developed by Angelidis and Neyret. Their method combines a very accurate representation of gas dynamics processes while also allowing for a high level of control by the artist. The process they described is based on vortex filament primitives, which is a fancy way of saying they are treating the swirls in a gas process as connected particles instead of a collection of individual entities. By connecting the stream of gas particles together, the physical accuracy of gas flows involved in smoke or explosions is increased. Researchers at Purdue University are also making advances in the area of modeling realistic gas process in an animated environment. Their novel approach is using the latest meteorological prediction software and algorithms to simulate gaseous weather phenomena like fog and cloud formation. They began with modeling cloud behavior and the effects of wind on clouds and saw that these same processes could be used to model other processes like steam, smoke and dust. Usually, a computer model of an object is only concerned with the properties and behavior of exterior surface of the object. The outside of an opaque object like a person, car or tree is the only surface you see in the movie. However, a cloud in the sky or fog moving along the ground has an interior that is visible because these objects are partially transparent. Modeling the physical processes is no longer limited to the exterior of the object. It also has to account for the dynamics of the interior of the object, which is more complicated for modeling. Although these processes are computationally intensive, the researchers at Purdue University have been able to optimize the simulation so that a developer can see their creation in real time without having to come back days later as was the normal procedure for doing animation.
The simulations developed by researchers, Angelidis and Neyret, and the cloud dynamics produced at Purdue university have used the physics of gas processes as a basis for developing sophisticated visual recreations of the real world. The advances made in modeling gas processes for animation have had a two-fold effect. First, the new and improved software and algorithms give more and better artistic control to the animators so they can create scenes exactly how they imagine them faster and more efficiently. Second, the audience will enjoy a more realistic experience at the theater because they are viewing images in an animated world that accurately depict things they are used to seeing in everyday life. The benefits probably do not stop with just the artists and the audience. The movie studios that employ these kinds of techniques can take advantage of the more realistic and connected experience to their movies that should show up in the form of impressive box office numbers and numerous film award nominations. I think it is important that researchers in collaboration with movie studios should continue to push the boundaries of animated movies. A society looking for the best in entertainment definitely benefits from a more intimate movie experience. Compare watching an early animated feature like Snow White or Bambi with more recently films like Up or Frozen. For the early features, you are aware that you are watching a cartoon because of the limits of hand-drawn animation. However, you are probably completely immersed in the more recent animated films because the images created in front of your eyes are so realistic. You forget you are watching a movie and it becomes more of an experience, which is exactly what you are paying for at the door. The tools available for movie creators and artists are now becoming almost limitless. As computing power and memory increases, the full artistic potential and creativity of the movie producers will be seen and shared with all of us. Finally, the cross collaboration of research and animated film production should continue to produce great advances in science and art. The applications used for science are being implemented in movie production and maybe the creations for animated films in Hollywood will help researchers better understand the physical world. I have seen the progression of animated films through the 1990s and 2000s and have never really given any thought to how my movie-going experience has changed with the technology being shown to me on the screen. In retrospect, I recognize that there is a tremendous amount of detail in today’s animated films that go unnoticed because you expect the processes taking place on screen to be just like the real world. After researching this topic, I more fully appreciate the efforts by scientists and researchers along with the graphic designers who have made the transition from the real world to the big screen so seamlessness that you don’t even realize you are watching animation.

REFERENCES

Angelidis, A. & Neyret, F. (2005). Simulation of Smoke based on Vortex Filament Primitives.
Symposium on Computer Animation. Retrieved from http://www-evasion.imag.fr/Publications/2005/AN05/paper0132.pdf

Boone, A.R. (1938). Snow White and the Seven Dwarfs: A Famous Fairy Tale Is Brought to the
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National Science Foundation. (2011). The Physics of Animation. Retrieved from http://www.nsf.gov/news/special_reports/science_nation/physicsanimation.jsp Oscars.org Education & Outreach. (2013). Animation: Activity 1 – The Origins of Animation.
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Pixar Studios. (2012). About – Our Story. Retrieved from http://www.pixar.com/about/Our-Story

Purdue University. (2003, July 17). Purdue Software Promises Better Animation For Movies, Games.
ScienceDaily. Retrieved from www.sciencedaily.com/releases/2003/07/030717090257.htm