Exploring Brick-Based Navigation and Composition in an Augmented Reality Morten Fjeld 1 , Fred Voorhorst 1 , Martin Bichsel 2 , Kristina Lauche 3 , Matthias Rauterberg 4 , and Helmut Krueger 1 1 Institute for Hygiene and Applied Physiology (IHA), Swiss Federal Institute of Technology (ETH), Clausiusstr. 25, CH-8092 Zurich {fjeld, voorhorst, krueger}@iha.bepr.ethz.ch www.fjeld.ch 2 Institute for Design and Construction Methods (IKB), Swiss Federal Institute of Technology (ETH), Tannenstr. 3, CH-8092 Zurich mbichsel@ikb.mavt.ethz.ch 3 Institute for Work and Organisational Psychology (IfAP), Swiss Federal Institute of Technology (ETH), Nelkenstr. 11, CH-8092 Zurich lauche@ifap.bepr.ethz.ch 4 Center for Research on User-System Interaction (IPO), Technical University Eindhoven (TUE), Den Dolech 2, NL-5612 AZ Eindhoven g.w.m.rauterberg@tue.nl Abstract. BUILD-IT is a planning tool based on computer vision technology, supporting complex planning and composition tasks. A group of people, seated around a table, interact with objects in a virtual scene using real bricks. A plan view of the scene is projected onto the table, where object manipulation takes place. A perspective view is projected on the wall. The views are set by virtual cameras, having spatial attributes like shift, rotation and zoom. However, planar interaction with bricks provides only position and rotation information. Object height control is equally constrained by planar interaction. The aim of this paper is to suggest methods and tools bridging the gap between planar interaction and three-dimensional control. To control camera attributes, active objects, with in- telligent behaviour are introduced. To control object height, several real and virtual tools are suggested. Some of the solutions are based on metaphors, like window, sliding-ruler and floor. 1 Introduction BUILD-IT is a planning tool based on computer vision technology, with a capacity for complex planning and composition tasks [19] [20]. The system enables users, grouped around a table, to interact in a virtual scene, using real bricks to select and manipulate objects in the scene (Fig. 1). A plan view of the scene is projected onto the table. A perspective view of the scene, called side view, is projected on the wall. The plan view H.-W. Gellersen (Ed.): HUC’99, LNCS 1707, pp. 102-116, 1999.  Springer-Verlag Berlin Heidelberg 1999