1. Constrained by knowledge Technology development and avatar design Kai-Mikael Jää-Aro Department of Numerical Analysis and Computer Science Royal Institute of Technology

2. “Avatar … an animated, articulated representation of a human which represents you, the user, in any virtual environment.”

3. “Any”? In fact, what an avatar is and what it does, is contingent on the specific situation and the available technology. The design principles for avatars have shifted over time with the prevalent interaction paradigm.

4. Early virtual environments Visual objects only, limited interaction, no distribution  no body representation.

5. Telepresence applications The teleoperated device is the body representation. It isnot determined by software and is adapted to the specific task.

6. Shared applications Body-tracked participants in an immersive virtual environment can be represented by humanoid figures. These support non-verbal communication, enable awareness of presence and indicate action. But, they are fundamentally limited to what the “master” human body can do.

7. Desktop environments User representations can be less human-like, but still indicate presence, support (some) non-verbal communication, but also convey information not tied to the user’s actual body. We retain our everyday applications on the desktop.

8. Dehumanising the avatar We can strive to give the avatar humanoid behaviour through available interaction tools. or Releasing the avatar from anthroporphism, we can add non-human abilities to it. Perception and interaction need not be tied to a single locus.

9. Navigation Navigation need not be moving through geometric space. Application- dependent navigation methods can move through interest space.

10. View control On a desktop we can have multiple views of the same environment. Navigation can then be treated as view selection.

11. Mixed realities exist simultaneously in physical and virtual spaces. No single user “owns” a given viewpoint/ actionpoint in the environment. Mixed Reality

12. Presence and intelligibility Participant’s understanding of their environment is constructed using available resources and is not crucially dependent on a “realistic” environment.