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This paper proposes a physics-based framework to control rolling, flipping and other behaviors with significant rotational components. The proposed technique is a general approach for guiding coordinated action that can be layered over existing control architectures through the purposeful regulation of specific whole-body features. Namely, we apply control for rotation through the specification and execution of specific desired ‘rotation indices’ for whole-body orientation, angular velocity and angular momentum control and highlight the use of the angular excursion as a means for whole-body rotation control. We account for the stylistic components of behaviors through reference posture control. The novelty of the described work includes control over behaviors with considerable rotational components, both on the ground and in the air as well as a number of characteristics useful for general control, such as flight planning with inertia modeling, compliant posture tracking, and contact control planning. [ABSTRACT FROM PUBLISHER]

We present a psychology-inspired approach for generating a character's anticipation of and response to an impending head or upper body impact. Protective anticipatory movement is built upon several actions that have been identified in the psychology literature as response mechanisms in monkeys and in humans. These actions are parameterized by a model of the approaching object (the threat) and are defined as procedural rules. We present a hybrid forward and inverse kinematic blending technique to guide the character to the pose that results from these rules while maintaining properties of a balanced posture and characteristics of the behavior just prior to the interaction. In our case, these characteristics are determined by a motion capture sequence. We combine our anticipation model with a physically-based dynamic response to produce animations where a character anticipates an impact before collision and reacts to the contact, physically, after the collision. We present a variety of examples including threats that vary in approach direction, size, and speed. [ABSTRACT FROM AUTHOR]

Human motion capture embeds rich detail and style which is difficult to generate with competing animation synthesis technologies. However, such recorded data requires principled means for creating responses in unpredicted situations, for example reactions immediately following impact. This paper introduces a novel technique for incorporating unexpected impacts into a motion capture-driven animation system through the combination of a physical simulation which responds to contact forces and a specialized search routine which determines the best plausible re-entry into motion library playback following the impact. Using an actuated dynamic model, our system generates a physics-based response while connecting motion capture segments. Our method allows characters to respond to unexpected changes in the environment based on the specific dynamic effects of a given contact while also taking advantage of the realistic movement made available through motion capture. We show the results of our system under various conditions and with varying responses using martial arts motion capture as a testbed. [ABSTRACT FROM AUTHOR]

A new generation of physics-based animation approaches are beginning to emerge that are robust and maintain a standard of visual quality as high as data-driven synthesis. And even with the holy grail of control principles that describe human motion still a mystery, the animation research community continues to forge its own path. We've learned that we don't need to solve the problem of biological control, nor do we need to throw out the advantages of animator control and motion capture. Instead, current research aims to find the best of all worlds, judiciously combining physics with human-motion examples, animator input, or both. This special issue brings together four examples of the innovations in this exploding area. [ABSTRACT FROM PUBLISHER]