Will.0.W1sp is an interactive installation exploring our ability to recognise human motion without human form. It uses particle systems to create characters or "whisps" with their own drifting, flowing movement, but which also follow digitised human movements. The central point of the environment is a 2x6m curved screen allowing the whisps to be projected at human scale while giving them enough to space to move and avoid visitors through the use of a combination of video tracking and motion sensors. The installation systems perform realtime motion analysis both on the prerecorded motion capture sequences and the movement of the audience to determine how to route the particles across the scene. The motion vectors are simultaneously fed to an audio system to create sound flowing in synch with the imagery. Will.0.w1sp invites visitors to chase after virtual, intangible characters which continually scatter and reform just beyond their reach.

This paper describes methods used to construct an interactive installation using human motion to animate both a visual and aural particle system. It outlines the rotoscoping, meta-motion processing, aural and visual rendering systems. It goes into detailed explanation of the "particle flow" systems which lend form to the virtual characters. The paper finishes with a description of the tracking system and "inverse interaction", used by the installation.