CAREER: Reusable, Realistic Motion Libraries for Computer Animation

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Animation is a tremendously powerful medium of expression.Ideas that would be complex or even impossible to expresswith still images or words can easily be conveyed usinganimated sequences. Unfortunately, even when the concept tobe conveyed via animation is simple, the process ofproducing the animation is inordinately difficult. Indeed,this is one of the reasons computer animation has become sodominant - it holds the promise of automating, and thussignificantly simplifying, the production process. Sadly,the process of transferring ideas into computer animationsis still far from simple. For example, the animated featurefilm Toy Story 2 required extremely hard work by as many as200 highly skilled computer and animation experts for morethan three years.My career goal is to develop the concepts and algorithmsthat will enable effortless, rapid development of realisticanimations that effectively convey the creator's purpose.This research hopes to create the theoretical andexperimental foundation for building much more powerfulanimation tools than exist today. Such tools will sharplyreduce the production time needed by skilled animators and,more importantly, enable average computer users to expresstheir ideas through animation. Such tools will also helpeducators teach more effectively and allow each one of us tobecome creators and directors of personal and fictionalstories. Only when animation production is easier willanimation be as commonplace on the web as images and textare today. Moreover, intuitive methods for creatingrealistic human motion will further enable the creation ofhuman avatars in tele-presence applications, newanthropomorphic human-computer interfaces, and realisticdigital actors in feature films and video games. Computeranimation will not achieve its full potential until 1)animation tools require little or no skill, 2) an animator'screativity is not stifled by the limitations of theanimation tools, and 3) the animation systems are availableto every person with a computer and a story to tell. I hopeto significantly contribute towards these goals.At the heart of this research is the observation that theanimator's creativity will not be fully realized until itbecomes easier to produce realistic motion sequences. Thisproblem is tremendously challenging because the underlyingphysical models of motion are difficult to create andcontrol. I believe that the solution lies in the creation ofhighly-flexible realistic motion libraries, together withtools to modify them intuitively and extensively. The powerof libraries stems from the ability to reuse alreadyexisting high-quality motion, reducing the need foranimation skills. In this paradigm, the process of animationturns into selecting the specific motion library, andmodifying a set of motion properties that transform theoriginal motion into a final animation.In my research, I propose to develop a methodology forcreating and using realistic motion libraries flexibleenough to be used in a wide range of applications. In 1995,I proposed the use of motion transformation as new way tocreate animations - a method fundamentally different fromthe traditional way of creating animations from scratch.This transformation approach is particularly useful formodifying realistic motion data captured from real-worldactors. Unfortunately, during the transformation process,much of the realism tends to be lost. Recently, I publisheda novel transformation approach which demonstrates thatanimations can be intuitively transformed into a wide rangeof new sequences without violating the fundamental dynamicproperties of motion. The realism is preserved bymaintaining a model of the dynamic and biomechanicproperties of the animated character.In the future, I will further develop mathematical modelsthat can be combined with real-world data to create reusablemotion libraries. Aside from preserving the realism ofmotion, the most important requirement for effective motionlibraries is the flexibility with which the libraries can beadjusted to meet the needs of an animator. I plan to achievethis flexibility by decomposing a character's motion into afundamental component and a style component in a waythat allows us to independently transfer these components tonew characters. For example, the animator can produce achild's cheerful run sequence by starting with a runningmotion library extracted from the captured human run. Thismotion can be modified by applying a happy, exuberant motionstyle, which is then transferred to an animated character ofa small child. Such decoupling of the fundamental motion,style, and performing character provides an extremelypowerful and flexible animation paradigm that can produce awide range of animations from a very small motion dataset.The main goal of the educational component of this proposalis to demonstrate the utility of advanced animation tools ineducation and story-telling. I am particularly interested inintroducing these new animation tools to Seattle high-schoolstudents to verify that our research does indeed empowerevery story-teller with an accessible medium of expression.I am also planning a project-oriented animation courseintended for undergraduate and graduate students involved inanimation research, as well as in art and music. Together,the students will work on using our tools to create anartistic short film project. This synergistic effort willexpose the artists to the latest animation technology andprovide direct user feedback to students involved inresearch. In addition, the created motion libraries as wellas the animation tools, will be freely distributed throughthe web and CDs with the hope that they will help animationbecome an effective communication medium across educational,economic and cultural boundaries.