Interactive motion deformation with prioritized constraints

Abstract

In this paper, we present an interactive motion deformation method to modify animations so that they satisfy a set of prioritized constraints. Our approach successfully handles the problem of retargetting, adjusting a motion, as well as adding significant changes to preexisting animations. We introduce the concept of prioritized constraints to avoid tweaking issues for competing constraints. Each frame is individually and smoothly adjusted to enforce a set of prioritized constraints. The iterative construction of the solution channels the convergence through intermediate solutions, enforcing the highest prioritized constraints first. In addition, we propose a new, simple formulation to control the position of the center of mass so that the resulting motions are physically plausible. Finally, we demonstrate that our method can address a wide range of motion editing problems.

Spatial relationship preserving character motion adaptation

“…Such an approach has been adopted for physically-based animation [Popović and Witkin 1999;Komura et al 2000;Liu and Popović' 2002;Fang and Pollard 2003], motion editing [Gleicher 1997;Callennec and Boulic 2004;Komura et al 2004;Liu et al 2006;Shum et al 2009] and motion retargeting [Gleicher 1998;Lee and Shin 1999;Choi and Ko 2000]. One of the early works by Gleicher [1998] handles close interactions of multiple characters.…”

Morphology‐independent representation of motions for interactive human‐like animation

“…As constraints are generally expressed in the Cartesian frame whereas joints are controlled using rotations, another solution consists in using inverse kinematics at each frame. This technique allows interactive motion deformation with prioritized constraints [CB04] including the control of the center of mass trajectory [BB04]. In order to decrease computation time, the method can be applied on only subsets of the entire kinematic chain [BCHB03].…”

Mesh puppetry

“…Unlike mesh deformation techniques that focus on shape and detail preservation, IK allows efficient design of large-scale deformation of skeletal figures through optimization of an energy functional in the null space of constraints. Current methods [Yamane and Nakamura 2003;Baerlocher and Boulic 2004;Le Callennec and Boulic 2006] even handle the fulfillment of conflicting constraints through prioritization, offering robust posture design.…”