San Francisco
Oct 26 and 27, 1996

Primer for E2A Avatar Discussions
Version 0.2, also see Version 0.1

This document is divided into three sections:

  • A glossary of terms
  • A description of the three "dimensions"
  • An examination of the technical issues
  • Note that his Primer will be evolving right up to the E2A conference, and quite possibly beyond it.


    There's a great deal of jargon associated with discussions of avatars and virtual environments. Here's a quick glossary to help you get started; it's in roughly alphabetical order. The parenthesized initials after some definitions indicate their source: MM=Moses Ma, BR=Bernie Roehl, BD=Bruce Damer, and so forth.

    An autonomous software entity that carries out some set of operations on behalf of a user, and in so doing, employs some knowledge of the user's goals or desires, with the minimal properties of autonomous interoperability, intelligence and authority. (MM)
    The combination of the functionality of an autonomous agent, with the audiovisual representation of an avatar. (MM)
    An autonomous software entity which emulates understood biological forms, seeks fitness to a niche, reproduces through some means and may or may not serve user's interests in its quest for survival. (BD)
    See Drone.
    There are many definitions of cyberspace. Mostly commonly, it refers to any environment which exists only within computer systems and the networks which connect them.(BR) The territory of Cyberspace where avatar-supporting environments are found is sometimes called Avatar Cyberspace. (BD)
    The avatar for another user, as displayed on your local computer system. A drone is remotely controlled by a Pilot. For each user on the system, there are as many drones as there are other users on the system.
    Lurker or Ghost
    Multi-User Virtual Reality.(BR)
    Observer Platform
    Essentially an "invisible avatar", which is capable of observing the events taking place in a multi-user virtual environment but which does not manifest itself in any way. (DIS) This type of avatar is also often called a lurker or ghost. (BD)
    The master copy of your avatar, which you control on your local computer system. A Pilot remotely controls all its drones. For each user on the system, there is exactly one pilot. (BR)
    See Drone.
    Real Life. The physical world we live in when we're not in a MUVR. Considered by some to be superior to virtual environments.
    Virtual Human
    Virtual World

    The Three "Dimensions "

    It's useful to treat the issues surrounding avatars in terms of three "dimensions": Philosophical, Human and Technological. All three are important, but different individuals will naturally be drawn to one or another of these three dimensions.

    The Philosophical Dimension

    The Human Dimension

    The Technological Dimension

    The technological dimension is concerned with the actual implementation of avatars and MUVR technology. In particular, it deals with issues of data structures, file formats, networking protocols, and so forth. This is a large enough topic that it will be dealt with separately below.

    The Technology of Avatars

    In order for any of the issues discussed above to have any real relevance, we must begin the job of actually implementing avatars and MUVR systems.

    There are four basic aspects of avatars that must be addressed:


    All aspects of an avatar's appearance. This includes such things as its hierarchical structure (hands attached to arms attached to chest and so forth), geometric description and surface properties (such as color and texture).


    The dynamically changing state of the avatar. This includes the positioning of the avatar in space, skeletal motion ("poses" or "positions") and muscular motion (such as facial expressions).


    The ability of the avatar to affect its environment and be affected by it. This includes such things as manipulating objects in the environment, communicating with other avatars using text or speech, exchanging data, and so forth.


    The relationship of an avatar to a real-world individual or organization. This includes such things as "true names", gender, links to other resources (such as web pages or email addresses), information necessary to enable financial transactions, and so on.

    Note that these should not be treated as rigid dividing lines. For example, it may not always be meaningful to discuss interaction independently of behavior, and some systems may treat identity as an aspect of representation.

    Discussion of these technical issues is extremely important, since the results will be fed back into the Virtual Humans Architecture Group (V-HAG), the Universal Avatars Group, and the Living Worlds Group.

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