DIVE: 3-D VR

MUD is an example of a textual ``VR'' application. The DIVE (Distributed Interactive Virtual Environment) [] system shows how it is possible to provide a more graphical VR for meeting support. A user or application is represented by an icon, which can move in a 3D space. The icon is associated with a space around it called the ``aura''. The notion of aura is used to establish communication between agents (users or applications) - the communication is established between two parties when the auras of their icons intersect. Communicating with applications means enabling them and with users mean perceiving them (talking and seeing.) Communication establishment is transitive, so if A's aura intersects B's aura, and B's aura intersects C's aura, then A and C can communicate with each other. Auras may be typed, and transitivity applies only to auras of the same type. Transitivity essentially allows auras to be amplified.

Several DIVE tools use this concept:

• Talk: When the auras of the icons of two users intersects, voice talk is enabled.

• Conference table: The conference table application also has an icon and two auras - an aura of perception and an aura of distribution. Users whose auras intersect the aura of perception, can talk to each other (even though their auras may not intersect directly) Users whose auras intersect with the aura of distribution get distributed active (shared) copies of documents placed on the table. Other users get private copies of the document.

• Podium service: A podium has two auras, an aura of perception and an aura of communication. A user within the aura of perception can speak to the audience in the aura of communication. Members of the audience cannot speak to each other or the speaker unless their auras intersect each other (directly or indirectly.)

• Single-user document editor: This is a single-user application and has an icon and aura. The application is enabled when a user's aura intersects this aura.

• Multiuser whiteboard: Each whiteboard has an aura. Users can interact with the whiteboard and talk to each other when their auras intersect the Whiteboard aura. Thus DIVE is also an example of a tool that integrates session- and artifact- based collaboration, which we shall study in more detail later.

Currently, I believe DIVE is a non-immersive VR application. It is easy to imagine an immersive extension, that allows a user to use a head-mounted display.