Armin Bruderlin

Motion signal processing

Techniques from the image and signal processing domain can be successfully applied to designing, modifying, and adapting animated motion. For this purpose, we introduce multiresolution motion filtering, multitarget motion interpolation with dynamic timewarping, waveshaping and motion displacement mapping. The techniques are well-suited for reuse and adaptation of existing motion data such as joint angles, joint coordinates or higher level motion parameters of articulated figures with many degrees of freedom. Existing motions can be modified and combined interactively and at a higher level of abstraction than conventional systems support. This general approach is thus complementary to keyframing, motion capture, and procedural animation.

The evolution of an interface for choreographers

This paper describes the evolution of the interface to Life Forms, a compositional tool for the creation of dance choreography, and highlights some of the important lessons we have learned during a six year design and implementation period. The lessons learned can be grouped into two categories: 1) Process, and 2) Architecture of the Interface. Our goal in developing a tool for choreography has been to provide computer-based creative design support for the conception and development of dance. The evolution was driven by feedback from the choreographers and users who were members of the development team, combined with our knowledge of current thinking on design and composition. Although the interface evolved in a relatively unconstrained way, the resulting system has many of the features that theoretical discussion in human interface design has projected necessary. The Life Forms interface has evolved incrementally with one major discontinuity where adoption of a new compositional primitive required a completely new version.

Procedural movement for articulated figure animation

Abstract The creativity and effectiveness of an animator can be enhanced with computer-based tools that incorporate knowledge about the problem being animated. This is particularly true of human figure animation, which is complex and has many degrees of freedom. Procedural systems that incorporate the knowledge directly into the algorithm are best suited to structured movements, which are often repeated whereas expert systems that reason on the basis of a knowledge base are best suited to more general and unstructured movement problems. This paper describes procedural movement generators for human locomotion and grasping. A few key parameters allow the animator to create a feasible movement pattern and additional movement attributes make it possible to customize the patterns to match the movement characteristics of the particular figure being animated. These procedural movement generators are being evaluated in the general purpose Life Forms system for human figure animation.

On the edge of the creative process: an analysis of human figure animation as a complex synthesis task

The process of animating human figures with a computer is a challenging task, both because the specification, reprt%entation and control of human movement is complex, and because animation as a human creative process is not well understood. Over the past six years, we have developed the LifeForms system, a computer application to animate human figures [2]. During this period, users of the system have played an active part in the design cycle their fkedback has lead to a better understanding of the interface for the representation of movement, while observing some of the users has given us insights into how the creative process can be supported by the system.

Animation of human gait

Abstract Recent developments in computer animation have made available more advanced methods to visualize human movements. These find application in entertainment, education, scientific visualization, ergonomic evaluation and as a medium for artistic expression. Two of the principal objectives which need to be addressed if human figure animation is to become more practical are the convenient, high level specification of movement sequences and the production of truly realistic movement. In order to provide convenient means of specifying movements there has been a tendency away from cell animation, where the user defines key positions in time, toward higher levels of control, where movements are specified as tasks like “walk to the door”. The computer “knows” about these tasks, decomposes them and calculates the proper joint angles over time. To attain a greater degree of motion realism techniques from robotics and biomechanics are being applied, where movements are generated through forces acting on masses of bodies. This paper introduces a method to animate human locomotion based on these principles. A generic locomotion cycle is derived from a simple dynamic model. The forces and torques which control this model are internally generated from knowledge about human gait. The mechanical and robot-like appearance of the simulated motion is visually enhanced and humanized through kinematic algorithms; a human leg is superimposed onto the simplified dynamic pendulum leg, a pelvis is induced and the arm swing and shoulder rotation during locomotion are expressed as functions of the lower body movements. The system which has been implemented can produce quite realistic looking human walks under a fairly wide range of conditions upon specification of only a few parameters, such as desired walking speed and step length. This will be extended in a straightforward way to running and locomotion over uneven terrain, up and down stairs, etc. Studies are also underway to determine how this approach can be applied to non-locomotory movement.

PROTOCOL ANALYSIS OF THE USE OF A CAD SYSTEM IN A HOME DESIGN TASK

The question of how humans design has been approached from a number of perspectives. Analyses have been made of the processes, strategies and problem solving techniques utilized when generating new designs [Finger 89]. One descriptive method to understanding the design process is the use of protocol analysis. This method has been successfully applied to elucidate the stages and decisions inherent in design (see, for instance, [Ullman 86, Adelson 89, Schon 88]).

The hair motion compositor: compositing dynamic hair animations in a production environment

Digital characters can appear in both live action and computer-animated movies. Most of them involve some form of dynamic hair or fur, often having to be both believable and heavily art-directed. No matter which dynamic hair solver a facility relies on, theres only so much that can be achieved with a physically realistic model, and most of the artists time is spent fixing or fine-tuning hair simulations to satisfy a Director or supervisor. To address this, Sony Pictures Imageworks developed the Hair Motion Compositor: a powerful hair animation framework that allows artists to direct, combine, offset and override hair animations that go in or come out of a dynamics solver.