We apply manipulation planning to computer animation. A new path planner is presented that automatically computes the collision-free trajectories for several cooperating arms to manipulate a movable object between two configurations. This implemented planner is capable of dealing with complicated tasks where regrasping is involved. In addition, we present a new inverse kinematics algorithm for the human arms. This algorithm is utilized by the planner for the generation of realistic human arm motions as they manipulate objects. We view our system as a tool for facilitating the production of animation.

Even such simple tasks as placing a box on a shelf are difficult to animate, because the animator must carefully position the character to satisfy geometric and balance constraints while creating motion to perform the task with a natural-looking style. In this paper, we explore an approach for animating characters manipulating objects that combines the power of path planning with the domain knowledge inherent in data-driven, constraint-based inverse kinematics. A path planner is used to find a motion for the object such that the corresponding poses of the character satisfy geometric, kinematic, and posture constraints. The inverse kinematics computation of the character’s pose resolves redundancy by biasing the solution toward natural-looking poses extracted from a database of captured motions. Having this database greatly helps to increase the quality of the output motion. The computed path is converted to a motion trajectory using a model of the velocity profile. We demonstrate the effectiveness of the algorithm by generating animations across a wide range of scenarios that cover variations in the geometric, kinematic, and dynamic models of the character, the manipulated object, and obstacles in the scene.

While interpolating between successive postures of an articulated figure is not mathematically difficult, it is much more useful to provide postural transitions that are behaviorally reasonable and that avoid collisions with nearby objects. We describe such a posture interpolator which begins with a number of pre-defined static postures. A finite state machine controls the transitions from any posture to a goal posture by finding the shortest path of required motion sequences between the two. If the motion between any two postures is not collision free, a collision avoidance strategy is invoked and the posture is changed to one that satisfies the required goal while respecting object and agent integrity. Keywords Human figure animation, motion control, posture interpolation, goal-directed behavior, collision avoidance, potential fields, self-collision, computer animation. 1 Introduction Postures are a very important aspect of human figure simulation. A static and recognizable postur...

KINEMATIC CONTROL OF HUMAN POSTURES FOR TASK SIMULATION XINMIN ZHAO NORMAN I. BADLER Kinematic control of human postures for task simulation is important in human factor analysis, simulation and training. It is a challenge to control the postures of a synthesized human figure in real-time on today's graphics workstations because the human body is highly articulated. In addition, we need to consider many spatial restrictions imposed on the human body while performing a task. In this study, we simplify the human posture control problem by decoupling the degrees of freedom (dof) in the human body. Based on several decoupling schemes, we develop an analytical human posture control algorithm. This analytical algorithm has a number of advantages over existing methods. It eliminates the local minima problem, it is efficient enough to control whole human body postures in real-time, and it provides more effective and convenient control over redundant degrees of freedom. The limitation of this a...

A method is presented for shape transformation in the plane. The primary strength of the proposed method over previous approaches for shape transformation is that our method can achieve shape transformation in a domain that can contain obstacles which are possibly in motion. A smooth transformation between two given polygonal shapes is to be attained while ensuring that any part of the shape is free of collision with the obstacles in the domain during the transformation process. The problem is formulated as minimization of a cost function associated with each transformation path that controls length, smoothness, and collision-freedom of the path. The problem is solved in three steps. First, a population of tentative transformation paths is generated by combining path planning for an anchor point in the shape and a randomization process. Second, collision detection and shape deformation techniques are applied to keyframes along the paths to minimize the occurrence of collisio...

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not be interpreted as representing the official policies, either expressed or implied, of any sponsoring institution, the U.S. The simulation of crowds of virtual characters is needed for applications such as films, games, and virtual reality environments. These simulations are difficult due to the large number of characters to be simulated and the requirement for synthesizing realistic human-like motion efficiently. This thesis focuses on two problems: how to search through and select motion clips of behaviors so that human-like motion can be generated for multiple characters interactively, and how to model and synthesize variation in motion data. Given a collection of blendable segmented motion clips derived from motion capture or keyframed animation, this thesis explores novel ways to apply heuristic search algorithms to generate goal-driven navigation motion for virtual humanlike characters. Motion clips are organized and interconnected through a behavior graph that encodes the possible actions of a character. A planning approach