1. MASSIVE “ Model, Architecture and System for Spatial Interaction in Virtual Environments ” a Distributed Virtual Reality System Incorporating Spatial Trading

2. The spatial model of interaction Scalability Scalability Aura Aura - In which it can interact (graphics, audio, text, etc.) - In which it can interact (graphics, audio, text, etc.) - defines interaction with other objects - defines interaction with other objects expressed as position possibly of other object attributes expressed as position possibly of other object attributes

4. The spatial model of interaction Spatial interaction awareness awareness - One object ’ s awareness of another object. In general, more attention - and more bandwidth and computation - will be devoted to objects with higher awareness values. - E.g. volume of audio detail of a graphical focus focus - the observer ’ s allocation of attention nimbus nimbus - the observed object ’ s manifestation or observability.

7. The spatial model of interaction implicitly implicitly through spatial actions such as moving and turning, e.g. when turning around my focus and nimbus follow me, resulting in an adjustment of my awareness of nearby objects through spatial actions such as moving and turning, e.g. when turning around my focus and nimbus follow me, resulting in an adjustment of my awareness of nearby objects explicitly explicitly by choosing from among different shapes and sizes, e.g. by choosing from among different shapes and sizes, e.g. switching between narrow or wide focus switching between narrow or wide focus Adapter objects Adapter objects which transform combinations of aura, focus and nimbus. which transform combinations of aura, focus and nimbus. communication tools (podium or a conference table) communication tools (podium or a conference table) boundaries boundaries segment space into regions and control how awareness flows across them segment space into regions and control how awareness flows across them group adapters (common auras, foci and nimbi for their members) group adapters (common auras, foci and nimbi for their members)

8. MASSIVE functionality Requirement: Requirement: Scale Scale as many simultaneous users as possible Heterogeneity Heterogeneity different styles of user interface Graphics, Audio, Text

9. MASSIVE functionality three settings for focus and nimbus three settings for focus and nimbus - normal, - normal, - narrow (intended for private conversations) - narrow (intended for private conversations) - wide (intended for browsing). - wide (intended for browsing). two adapter objects are provided: two adapter objects are provided: - A podium which extends the aura and nimbus of its user; - A podium which extends the aura and nimbus of its user; - A conference table which replaces its users ’ normal auras, foci and nimbi with new sets which span the table. - A conference table which replaces its users ’ normal auras, foci and nimbi with new sets which span the table.

11. MASSIVE architecture a communications architecture based on typed a communications architecture based on typed peer-peer connections (of which client- server connections are a sub-set) which utilise a combination of RPCs, shared attributes and streams; peer-peer connections (of which client- server connections are a sub-set) which utilise a combination of RPCs, shared attributes and streams; a spatial trading mechanism to dynamically broker interfaces following aura collisions a spatial trading mechanism to dynamically broker interfaces following aura collisions dynamic interaction between client programs supporting different media. dynamic interaction between client programs supporting different media.

12. MASSIVE architecture Communications architecture Communications architecture combination of remote procedure calls (RPCs), attributes and streams. combination of remote procedure calls (RPCs), attributes and streams. the client must first form a connection between one of its own interface ’ s and the client must first form a connection between one of its own interface ’ s and the server ’ s interface. the server ’ s interface. client-server style services (e.g. trading and spatial trading, coordination of auser ’ s textual, audio and graphical clients), others are strictly peer-to-peer. client-server style services (e.g. trading and spatial trading, coordination of auser ’ s textual, audio and graphical clients), others are strictly peer-to-peer.

13. MASSIVE architecture Aura and spatial trading Aura and spatial trading Interaction between objects in the virtual world (two conditions) Interaction between objects in the virtual world (two conditions) 1) Client must be established that the objects involved possess some compatible interfaces; compatible interfaces; 2) the objects must become sufficiently proximate as determined by their auras (separate aura for each interface) Aura Manager Aura Manager New object declares its interfaces as service offers, each with its own aura. Each aura manager handles one or more worlds, each with its own set of media. As objects change worlds they may be passed from one aura manager to another.

15. MASSIVE architecture Implementation of focus and nimbus Implementation of focus and nimbus Focus and nimbus Mathematical functions -> attributes of the communicating objects (focus and nimbus values)-> mutual awareness levels. spatial attributes (e.g. position and orientation) non-spatial attributes Connected objects exchange information

16. MASSIVE architecture Integration of client programs Integration of client programs Three kinds one for each of the audio, graphics and text media Portals Portals Portals are gateways between different worlds, or between different locations within the same world. Attribute : destination location e.g. new world name ( may aura manager) e.g. new world name ( may aura manager)

17. MASSIVE communication communication The interactions in MASSIVE are a mixture of client-server (between objects and the trader or aura manager) client-server (between objects and the trader or aura manager) peer-to-peer (between objects in the world). peer-to-peer (between objects in the world).