Smooth movers: perceptually guided human motion simulation

To animate a character, a number of poses are displayed in quick succession in order to create the illusion of motion. For most real-time applications, such as games, the pose update rate is largely constrained by the available hardware and overall simulation complexity. To date, no analysis of the factors that affect the perceived smoothness of animated virtual characters has been presented. In the first perceptual studies aimed at identifying such factors and their interactions, we have determined some thresholds that could be used to produce acceptably smooth human animations in a variety of conditions. Some interesting results were found, e.g., that character type, clothing, scene complexity or motion synchronicity had no effect on smoothness perception in our experiments, but cycle rate, linear velocity, motion complexity and group size all had a significant effect, with slower or lower intensity movements generally requiring fewer updates. Our results should be of real practical use to character animators in various application areas, but in particular to developers of real-time applications where Simulation Levels Of Detail (SLOD) need to be employed.