Mobility and Social Interaction as Core Gameplay Elements in Multi-Player Augmented Reality Alessandro Mulloni Graz University of Technology Inffeldgasse 16 8010 Graz (Austria) mulloni@icg.tugraz.at Daniel Wagner Graz University of Technology Inffeldgasse 16 8010 Graz (Austria) wagner@icg.tugraz.at Dieter Schmalstieg Graz University of Technology Inffeldgasse 16 8010 Graz (Austria) schmalstieg@tugraz.at ABSTRACT In this paper, we present an Augmented Reality game that strongly exploits mobility and social interaction between players as core gameplay elements. We have implemented this game on handheld devices and conducted a qualitative user study, investigating the level of mobility and social involvement of players. We discuss the results from this user study, describing the problems experienced by players and how we tackled them. Categories and Subject Descriptors H.5.1 [Information Interfaces and Presentation]: Multimedia Information Systems – Artificial, augmented, and virtual realities; K.8.0 [Personal Computing]: General – Games; General Terms Design, Experimentation, Human Factors. Keywords Augmented Reality Games, Mobility, Handheld Augmented Reality. 1. INTRODUCTION An advantage of playing games in the real world is that navigation in the environment and communication between players are performed in natural ways. The interface with the real world is intuitive and well known to players of any age, sex and technical expertise. People get involved socially and physically with the same mechanics they regularly use also in non-gaming contexts. On the other hand, computer games have the advantage of allowing sophisticated, animated content, which is sometimes fantastic or even impossible in the real world. Computer games can challenge players independently from the availability of human opponents. A computer is also an unbiased game controller that can enforce complex game rules and verify multiplayer game actions. A natural strength of Augmented Reality (AR) games is that real- world interaction and computer-controlled content can be mixed seamlessly. This is especially true when unobtrusive devices are adopted, as in the case of handheld game consoles and mobile phones. Players can easily combine device-mediated and real- world interaction paradigms in a single homogeneous game experience. We present a team-based competitive AR game that requires players to physically explore the game environment and to communicate face-to-face with other players. We implemented the game on lightweight handheld game devices and conducted an explorative user study with a group of technically as well as non- technically educated players. We believe that the results from this study can be of help for researchers working on AR in mobility contexts as well as for companies working on commercial AR games. This paper is structured as follows: section 2 compares our project to related work and presents our motivation for the project; section 3 presents the game, its gameplay and what is necessary to set up the game in a new environment; section 4 gives details on the implementation; section 5 presents first empirical observations on the gameplay; section 6 introduces a qualitative user study that we carried out and results which derived from it. Finally we draw conclusions and discuss future work. 2. MOTIVATION AND RELATED WORK The proposed game draws inspiration from various categories of computer-based and computer-less gaming; we try to mix elements from various categories into an original gameplay suitable for casual players. A core element of this game is mobility: players are forced to physically explore the environment looking for game locations. Mobility elements can already be found in non-computer games such as “hide and seek” and treasure hunts. Another gameplay element that is shared with treasure hunts is the spatial search for hidden items: in our game, virtual cows are scattered around the real environment and players are required to look for them. Most AR games on mobile devices, such as AR Tennis [6], the Invisible Train [11] or the work done by Rohs [8], are portable rather than mobile. They exploit mobility only around a central game board, instead of integrating the real environment into the game. Some marker-based edutainment games, such as the Eduventure [5] and MARQ [9], strongly foster explorative mobility of the players inside the environment. In the educational games the locations have usually the role of disconnected checkpoints that make up a Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. DIMEA’08, September 10–12, 2008, Athens, Greece. Copyright 2008 ACM 978-1-60558-248-1/08/09…$5.00.