Human movements include limb gestures and postural attitude. Although many computer animation researchers have studied these classes of movements, procedurally generated movements still lack naturalness. We argue that looking only at the psychological notion of gesture is insufficient to capture movement qualities needed by animated characters. We advocate that the domain of movement observation science, specifically Laban Movement Analysis (LMA) and its Effort and Shape components, provides us with valuable parameters for the form and execution of qualitative aspects of movements. Inspired by some tenets shared among LMA proponents, we also point out that Effort and Shape phrasing across movements and the engagement of the whole body are essential aspects to be considered in the search for naturalness in procedurally generated gestures. Finally, we present EMOTE (Expressive MOTion Engine), a 3D character animation system that applies Effort and Shape qualities to independently defined underlying movements and thereby generates more natural synthetic gestures. ABSTRACTHuman movements include limb gestures and postural attitude. Although many computer animation researchers have studied these classes of movements, procedurally generated movements still lack naturalness. We argue that looking only at the psychological notion of gesture is insufficient to capture movement qualities needed by animated characters. We advocate that the domain of movement observation science, specifically Laban Movement Analysis (LMA) and its Effort and Shape components, provides us with valuable parameters for the form and execution of qualitative aspects of movements. Inspired by some tenets shared among LMA proponents, we also point out that Effort and Shape phrasing across movements and the engagement of the whole body are essential aspects to be considered in the search for naturalness in procedurally generated gestures. Finally, we present EMOTE (Expressive MOTion Engine), a 3D character animation system that applies Effort and Shape qualities to independently defined underlying movements and thereby generates more natural synthetic gestures.

Computer synthesized characters are expected to make appropriate face, limb, and body gestures during communicative acts. We focus on non-facial movements and try to elucidate what is intended with the notions of "gesture" and "naturalness". We argue that looking only at the psychological notion of gesture and gesture type is insufficient to capture movement qualities needed by an animated character. Movement observation science, specifically Laban Movement Analysis and its Effort and Shape components with motion phrasing provide essential gesture components. We assert that the expression of movement qualities from the Effort dimensions are needed to make a gesture naturally crystallize out of abstract movements. Finally, we point out that non-facial gestures must involve the rest of the body to appear natural and convincing. A system called EMOTE has been implemented which applies parameterized Effort and Shape qualities to movements and thereby forms improved synthetic gestures. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This journal article is available at ScholarlyCommons: http://repository.upenn.edu/hms/5 AbstractComputer synthesized characters are expected to make appropriate face, limb, and body gestures during communicative acts. We focus on non-facial movements and try to elucidate what is intended with the notions of \gesture" and \naturalness". We argue that looking only at the psychological notion of gesture and gesture type is insucient to capture movement qualities needed by an animated character. Movement observation science, specically Laban Movement Analysis and its Eort-Shape dimensions with motion phrasing provide essential gesture components. We assert that the expression of movement qualities from the Eort dimensions are needed to make a gesture naturally crystallize out of abstract movements. Finally, we point out that non-facial gestures must involve the rest of the body to appear natural and convincing. A system called EMOTE has been implemented which applies parameterized Eort and Shape qualities to movements and thereby forms improved synthetic gestures.

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llioo-nrbal behaviors have a key role in making a Virtual Character appear life-like. We describe an extensible sy §tem for the specification, control and real-time generation of facial expressions and gestures. The system approximates In a MPEG-4 based Virtual Character the wide expressive range, dynamism (an expression's meaning significantly depends on its temporal evolution) and "ariability (an emotion is never expressed exactly in the same wa�' by different people, and e\'en by the same person at different times), typical of human non· nrbal behayior. The I\1PEG-4 standard only allows high-level control of 6 basic emotions, and does not expllcitly support the description of an expression temporal evolution. Our approach has been that of creating a hierarchical model of expressiveness; expressions are defined in term of parameterized functions controning low-Ie"el aDimation parameters trajectories (by means of an XML-based Expression Definition ]U arkup Language). The real-time generation of those expressions is performed by an Expression Synthesis Engine. The system allows to effectively modulate expressivity both at design-time (the denloper tweaks the parameters to give the character a gh'en expressive style), and at run-time (the engine automatically changes the way jD which an expression is performed each time),producing controllable, but Don-deterministic, beha,ior patterns, a key factor for enhandng belle\·ability.