Keyframe Animation of Articulated Figures Using Autocollision-Free Interpolation

Keyframing is a popular method for animating articulated figures because it allows artistic expressiveness by providing control to the animator. The animator defines a movement by providing a set of poses. The motion is then obtained by simply interpolating between these keyframes, typically with cubic splines. The drawback of this process is that it requires significant effort from the animator. Defining a movement often requires a high level of detail to ensure that the interpolation curves induce the desired motion. In particular, the animator has to focus on avoiding collisions between the limbs of his or her articulated figure. The paper describes a new interpolation method producing autocollision-free paths. A first interpolation is computed using any classical inbetweening method. Autocollisions are then identified and corrected if necessary. At some collision times, autocollision-free sub-keyframes are automatically generated using geometric properties. They are then used for obtaining an autocollision-free interpolation. Experimental results using a human model show that the animator can reduce the level of detail needed for describing a movement and still get realistic results at interactive speeds.