«From Linear to Interactive Animation: How Autonomous Characters Change the Process and Product of Animating BILL TOMLINSON University of California, ...»
From Linear to Interactive Animation:
How Autonomous Characters Change
the Process and Product of Animating
University of California, Irvine
There are significant differences between the art of animating for linear media such as film and video and the
art of animating for interactive media such as computer and video games. In particular, these differences arise from the shift from linear characters to autonomous interactive characters. This article describes differences between linear animation and interactive animation in several areas of character design – character intelligence, emotional expressiveness, navigation, transitions among animations, and multi-character interaction. These differences provide insight into the processes of both forms of animation and the final products that they create, and may provide a starting point for linear animators interested in becoming familiar with interactive animation.
Categories and Subject Descriptors: I.3.7. [Computer Graphics]: Three-Dimensional Graphics and Realism— Animation; I.3.6 [Computer Graphics]: Methodology and Techniques—Interaction techniques Categories and Subject Descriptors: I.3.7. [Computer Graphics]: Three-Dimensional Graphics and Realism— Animation; I.3.6 [Computer Graphics]: Methodology and Techniques—Interaction techniques.
General Terms: Design, Human Factors Additionak Key Words and Phrases: Animation, Production, Games, Interactivity __________________________________________________________________________________________
Animation is the art of breathing life into things—creating the appearance of motion, behavior and personality in characters and other entities. When most people use the term “animation,” they think of Bugs Bunny, Buzz Lightyear, and other traditional animated characters. In the last few decades, animation has also become significantly associated with interactive media such as computer and video games. While there are many similarities between the forms of animation that generate linear and interactive products, there are also profound differences. These differences are not necessarily obvious to the consumers of the two forms, who ultimately experience both as images flickering across screens. This article offers an account of some of the ways in which the interactive animation process is different from (and usually harder than) more linear forms of animation. Considering the differences in the processes of these two kinds of animation may contribute to an understanding of the differences between the aesthetic forms that they produce.
At a very high level, linear and interactive animations share a common goal—to create an engaging experience for the viewer/player. In comparing film and interactive mediated environments, Marsh  offers three levels of experience that produce engagement: voyeuristic (the joy of seeing the new and the wonderful), visceral (thrill of __________________________________________________________________________________________
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spectacle and attractions), and vicarious (transfer of emotion through another person,being or object) [Marsh 2003]. The characters in both linear and interactive animation lie at the heart of these three levels of experience, and are particularly central to the third. Accordingly, the differences between the characters in these two forms of media are central to an understanding of the differences between the media themselves.
ACM Computers in Entertainment, Vol. 3, No. 1, January 2005.
From Linear to Interactive Animation • 3 This article discusses five main differences between linear and interactive characters, including the locus of intelligence in the characters, how the characters are made to express themselves emotionally, how the characters navigate around their world, how the characters transition between actions, and how characters interact with each other. Table I offers a summary of these key differences. Each item gives a brief summary of the topic from the perspectives of linear animation and interactive animation. The brief descriptions in this table are necessarily generalizations; there are exceptions to each of these topics, and active research in all of these areas. These issues will be addressed more fully in the sections that follow the list.
By directly addressing the differences between the two kinds of animation, this article seeks to understand the capabilities of the two media. Many books have been written on the topic of traditional film animation (e.g., [Laybourne 1998; Thomas and Johnson 1981]. In addition, several books have been written on animating for video games (e.g., [Steed 2002]). This article seeks to understand the ways in which the processes of making characters for linear and interactive animation affect the content that these two forms produce.
1 EXAMPLES OF LINEAR AND INTERACTIVE ANIMATIONIn order to establish a common background, this article first gives a brief description of the production pipelines for linear animation and interactive animation. In addition, this section provides brief descriptions of two animated projects by the author and his collaborators: one linear and one interactive.
1.1 Linear The linear animation process may take on a number of forms. The most widely known is the production pipeline used to create animated narrative feature films such as Dreamworks’ Shrek or Disney’s The Lion King. While different studios employ different
pipelines, a typical production might use the following steps:
• a screenplay is written that prescribes the ordering of events in the final film;
• a series of storyboards is drawn that depicts each event;
• a soundtrack is recorded using human actors;
• numerous scenes are animated simultaneously to match the storyboards and soundtrack with different animators working on different characters and scenes;
• the film is edited into the correct order, and revisions are made to both soundtrack and animation;
• the final picture and sound are printed to celluloid film;
• the film is distributed to theaters and shown to large audiences.
Before a complete film can be created, a great deal of coordination must occur among producers, directors, animators, actors, sound designers, technical directors, editors, publicists, projectionists, and many others. Different animation techniques such as cel animation, 3D computer animation, stop-motion animation, or cut-out animation add additional constraints to this process.
While most animated features adhere to some variant of the above process, independent animators use smaller crews and a wider range of production processes to create their films. As an example of one production pipeline, in 1995-6 the author made
a stop-motion animated film called Shaft of Light (see Figure 1). This production began with a short script, which was produced as a stage play using human actors. Thereafter, the film was storyboarded and the characters were constructed from brass tubing, wire, and hot glue. Once the characters were complete, there was a 12-day film shoot during which approximately 14 minutes of raw footage (~20,000 images) were generated. In the 4 weeks following the shoot, the raw footage was developed and edited down to its final length of 8 min. 46 sec. Then the actors recorded the voices of the characters and the composer created all of the composition and sound design. (This order of production is quite different from the traditional animated feature process described above, where the voice recording is done first and the animation is made to match.) Finally, a 16mm celluloid print was made, and copies of the film were distributed to film festivals. An
online version of the film may be seen at the following web address :
1.2 Interactive Large-scale interactive animation productions, like those used in making character-based video and computer games, employ a very different set of processes than those described above for linear animation. The game industry is significantly younger than the film/animation industry, having been in existence for less than half as long. Spacewar in 1962 could be considered the first “real computer game” [DeMaria and Wilson 2003, p.12], whereas filmed animation developed as a medium in the nineteenth century [Bendazzi 1995]. Due to its relative youth, the game industry is still undergoing rapid change in its production processes.
Despite the wide variety of production pipelines in place in game companies, there are certain processes that unify many current 3D animated, character-based computer and video game productions. Interactive animations are conceptualized by a small team of designers, artists, software engineers and producers. A team of software engineers creates a game engine that will serve as a computational platform for the game (or they decide to license and reuse an existing engine). The animated characters are modeled and rigged (that is, given a computationally sound infrastructure so that the animators can produce content that may be integrated into the game) by a group of artists, animators, ACM Computers in Entertainment, Vol. 3, No. 1, January 2005.
From Linear to Interactive Animation • 5 and technical directors. Animators generate the characters’ behavioral repertoire, using a 3D animation program, motion capture technologies, or other custom tools. Software engineers create the code that controls the behavior of the characters and the dynamics of the virtual world and connects the interface elements (buttons, etc.) for game play. This kind of game often consists of a group of levels or areas (similar to scenes in a play or movie); these subsections are created by level designers using tools designed by software engineers and technical directors. Lighting designers, virtual cinematographers, and audio directors contribute additional elements to the game. Finally a team of quality assurance testers plays the game thoroughly to find bugs, which are then sent back to the software engineers, designers, and animators. Once the game is complete, it is distributed to its players through stores and online retailers.
Similar to the independent animators described above, there are numerous smaller teams making independent interactive animations as well. One example is the production of a 3D animated interactive installation entitled AlphaWolf [Tomlinson et al. 2001] (see Figure 2) by the author and other members of the Synthetic Characters Group at the MIT Media Lab. The installation featured a virtual pack of wolves that participants could direct by howling, growling, whining, or barking into microphones [Tomlinson et al.
2002]. This production started from a code base for building interactive characters and virtual installations that has been in development and use since 1997 [Blumberg 1998;
1999]. In the winter and spring of 2001, a prototype of the installation was developed with simple 3D models, animation and programmed behavior. In the summer of that year, five programmer/interface designers, two animators, and a sound designer worked in the same room for approximately three months to build the final installation. The development process involved very close collaboration among the creators and a tight feedback loop between the programmers, interface designers, animators, and sound online at designer. This interactive installation premiered at SIGGRAPH 2001, and has been exhibited at a number of other venues since then. For a better sense of the installation, please see the episode of the PBS television show Scientific American
Frontiers, hosted by Alan Alda on 10/22/02, available http://pbs-saf.virage.com/cgibin/visearch?user=pbssaf&template=template.html&query=Alpha+Wolf&category=0&vi Keyword=Alpha+Wolf