From Interaction to Trajectories Steve Benford Mixed Reality Laboratory University of Nottingham

Desert Rain (1997)

Uncle Roy All Around You (2003)

Fairground: Thrill Laboratory (2006)

Day of the Figurines (2006)

Trajectories All four experiences combine interactivity with live performance They also exhibit complex and extended spatial and temporal structures They are unified by the approach of creating a coherent journey through the experience Building on recent studies of interactive exhibits, these journeys can be described in terms of trajectories

Trajectories through hybrid space Mixed Reality Continuum (Milgram and Kishino) Virtual Reality (Everyday) Reality Augmented Reality Augmented Virtuality immersion ubiquity Our experiences combine multiple points on the continuum to form complex hybrid space through which participants move

Trajectories through hybrid time Time as perceived by the participant Perceived time The timing of interactions as perceived by the participant Interaction time The times at which a participant chooses or is able to interact Schedule time The times at which the narration is made available Plot time The temporal structure of the narration of the story Story time The temporal structure of the underlying story world Time as conceived by the author

Trajectories through roles Participants Street players Online players each role follows its own trajectory and there are trajectories between roles Performers Actors Orchestrators Spectators Audience Bystanders

Trajectories through interfaces Interfaces are designed and also arranged to establish a trajectory of interaction

Transitions and Traversals Trajectories have to negotiate various transitions and traversals during which continuity may be at risk

Transitions and Traversals beginnings Trajectories have to negotiate various transitions and traversals during which continuity may be at risk

Transitions and Traversals Role and interface transitions beginnings Trajectories have to negotiate various transitions and traversals during which continuity may be at risk

Transitions and Traversals Role and interface transitions Temporal episodes beginnings Trajectories have to negotiate various transitions and traversals during which continuity may be at risk

Transitions and Traversals Role and interface transitions Temporal episodes Physical-virtual traversals beginnings Trajectories have to negotiate various transitions and traversals during which continuity may be at risk

Transitions and Traversals Role and interface transitions Temporal episodes Physical-virtual traversals beginnings Access to physical resources Trajectories have to negotiate various transitions and traversals during which continuity may be at risk

Transitions and Traversals Role and interface transitions Temporal episodes Seams Physical-virtual traversals beginnings Access to physical resources Trajectories have to negotiate various transitions and traversals during which continuity may be at risk

Transitions and Traversals Role and interface transitions endings Temporal episodes Seams Physical-virtual traversals beginnings Access to physical resources Trajectories have to negotiate various transitions and traversals during which continuity may be at risk

Negotiating Trajectories Canonical trajectory Participant trajectory Canonical and participant trajectories represent an author’s ideal journey and a participant’s actual journey respectively

Negotiating Trajectories Canonical trajectory Interactivity drives divergence Participant trajectory Canonical and participant trajectories represent an author’s ideal journey and a participant’s actual journey respectively

Negotiating Trajectories Orchestration drives convergence Canonical trajectory Participant trajectory Canonical and participant trajectories represent an author’s ideal journey and a participant’s actual journey respectively

Interleaving Trajectories Participant ‘red’ Participant ‘blue Multiple trajectories can represent different participants or different applications

Interleaving Trajectories Mutual awareness and encounters when trajectories come together Participant ‘red’ Participant ‘blue Multiple trajectories can represent different participants or different applications

Interleaving Trajectories Participant ‘red’ Participant ‘blue Steer trajectories apart to avoid contention or to minimise distractions and interruptions Multiple trajectories can represent different participants or different applications

Interleaving Trajectories Participant ‘red’ Pacing involves keeping trajectories together Participant ‘blue Multiple trajectories can represent different participants or different applications

Summary of Trajectories A trajectory describes a journey through an extended user experience emphasising continuity and coherence Trajectories pass through hybrid structures of space, time, roles and ecologies of interfaces Trajectories have to cross key transitions including beginnings, endings, role and interface transitions, physical-virtual transitions, temporal episodes, physical resources and seams Canonical trajectories and participant trajectories represent author and participant control and diverge and converge due to interactivity and orchestration Interleaved trajectories describe collaborative and/or multi-tasking situations and address encounters, awareness, separation, pacing and prioritisation

Putting Trajectories to Work Providing sensitising concepts for empirical studies A vehicle for compiling craft knowledge Identifying requirements for new technologies Towards a dramaturgy of interactive user experience

‘Serious’ experiences? Cultural experiences may provoke reflection and debate Addressing challenging themes Using ambiguity to provoke interpretation Wider applications of trajectories Designing complete VR experiences Supporting learning

Further Information www.mrl.nott.ac.uk www.blasthoery.co.uk www.thrilllaboratory.com Papers and videos available at: www.mrl.nott.ac.uk/~sdb Benford, Giannachi, Koleva & Rodden, ‘From Interaction to Trajectories: Designing Coherent Journeys Through User Experiences’, ACM CHI 2009 Benford &Giannachi, ‘Temporal Trajectories in Shared Interactive Narratives’, ACM CHI 2008 Benford et al, ‘The Frame of the Game’, ACM CHI 2006 Reeves, Benford, O’Malley and Fraser, ‘Designing the Spectator Interface, ACM CHI 2005 Gaver, Beaver & Benford, ‘The Role of Ambiguity in Interfac Design’, ACM CHI 2003