We’ve come up with something that I think is quite cool for conveying presence though our avatars. Interpretive Motion IK is a technique in which all kinds of inputs drive a small set of animated motions, and then the animation results and additional inputs both drive an Inverse Kinematic system. This gives us a rich set of built-in avatar behaviors, while also making use of an ever-evolving set of input devices to produce a dynamic and life-like result.
Why Aren’t Avatars More Like Us?
From static “head shots” in a text chat, to illustrations in a book and famous faces in a movie, avatars give us an intuitive sense of who is present and who is doing what. The story of an animated movie (or high end game “cut scene”) is largely shown through the fluid motion of anthropoids. A movie studio can hire an army of artists, or record body actors in motion capture suits. But a virtual world does not follow a set script in which all activity can be identified and animated before use. Avatar animation must instead be generated in real time, in response to a world of possible activities.
This challenge leads some systems to just show users as simplified images, or as just a head, a disembodied “mask and gloves”, or a mostly un-animated “tin can” robot. This may be appropriate for specialized situations, but in the general case of unlimited high fidelity virtual worlds, the lack of whole-body humanoid animation fails to provide a fulfilling sense of personal immersion.
When it works well, the interpretation of motion is so strong that when another avatar turns to face your avatar, we describe it as “YOU can see ME”. In fact, the pixels on the screen have not turned, and cannot see. Think of the personality conveyed by the Pixar desk lamp hopping across the scene and looking at the camera, or the dancing skeletons of Disney’s early Silly Symphony. Unlike Disney and Pixar, High Fidelity aims to capture this rich whole-body movement as a realtime result of dynamic user input. Alas, today’s input devices give us only incomplete data. Interpretive Motion IK allows us to integrate these clumsy signals into a realistic sense of human personality and action.
