Synthesis of Realistic Idle Motion for Interactive Characters

Egges, A. and Giacomo, T. Di and Magnenat-Thalmann, N.

Abstract: In this article, we will discuss a class of motions that is often ignored in game development, but that is crucial for creating realistic character movement: idle motions. In nature there exists no motionless character, while in games we often encounter cases where no planned actions, such as waiting for another character finishing his/her part, are implemented as a stop/frozen animation. We will present an architecture that will allow you to automatically generate idle motions as a part of the character animation engine in your game. Our approach overcomes the limitations of using a small set of existing clips as a basis for synthesizing idle motions. Direct use of a small set of animations results in unnatural repetition of movements and difficulties inserting idle motions into an animation without breaking its continuity. Our animation engine uses an exponential map representation for rotations, on which we apply a Principal Component Analysis (PCA). The PCA significantly reduces the dimension of the animation space and therefore allows for faster transfer of animation data, which is very useful for online gaming. Because of the reduced dimensionality, different motions can be generated very quickly while still retaining the dependence between different joints. The result is a wide variety of animations that are consistently realistic.

  booktitle = {Game Programming Gems 6},
  author = {Egges, A. and Giacomo, T. Di and Magnenat-Thalmann, N.},
  title = {Synthesis of Realistic Idle Motion for Interactive Characters},
  publisher = {Charles River Media, Mike Dickheiser (ed.)},
  pages = {409-422},
  month = mar,
  year = {2006},
  topic = {Motion Capture, Body Animation and Control}