A Motion Control Scheme for Animating Expressive Arm Movements

A MOTION CONTROL SCHEME FOR ANIMATING EXPRESSIVE ARM MOVEMENTS Diane M. Chi Supervisor: Norman I. Badler Current methods for gure animation involve a tradeo between the level of realism captured in the movements and the ease of generating the animations. We introduce a motion control paradigm that circumvents this tradeo |it provides the ability to generate a wide range of natural-looking movements with minimal user labor. E ort, which is one part of Rudolf Laban's system for observing and analyzing movement, describes the qualitative aspects of movement. Our motion control paradigm simpli es the generation of expressive movements by proceduralizing these qualitative aspects to hide the non-intuitive, quantitative aspects of movement. We build a model of E ort using a set of kinematic movement parameters that de nes how a gure moves between goal keypoints. Our motion control scheme provides control through E ort's fourdimensional system of textual descriptors, providing a level of control thus far missing from behavioral animation systems and o ering novel speci cation and editing capabilities on top of traditional keyframing and inverse kinematics methods. Since our E ort model is inexpensive computationally, E ort-based motion control systems can work in real-time. We demonstrate our motion control scheme by implementing EMOTE (Expressive MOTion Engine), a character animation module for expressive arm movements. EMOTE works with inverse kinematics to control the qualitative aspects of end-e ector speci ed movements. The user speci es general movements by entering a sequence of goal positions for each hand. The user then expresses the essence of the movement by adjusting sliders for the E ort motion factors: Space, Weight, Time, and Flow. EMOTE produces a wide range of expressive movements, provides an easy-to-use interface (that is more intuitive than joint angle interpolation curves or physical parameters), features interactive editing, and real-time motion generation.