Specifying the Representation of Non-geometric Information in 3D Virtual Environments Kaveh Bazargan and Gilles Falquet CUI - University of Geneva 7, route de Drize, CH-1227 Carouge, Switzerland {kaveh.bazargan,gilles.falquet}@unige.ch Abstract. In 3D virtual environments (3DVE), we need to know what an object looks like (i.e. geometric information) and what the object is, what are its properties and characteristics and how it relates to other objects (i.e. non-geometric information). Several interactive presentation techniques have been devised to incorporate non-geometric information into 3DVEs. The relevance of a technique depends on the context. Therefore, the choice of an appropriate representation technique cannot be done once for all and must be adapted to the context. In this paper, we first present a preliminary classification of representation techniques for non- geometric information in 3DVE. Then we propose a formalism, based on description logics, to describe the usability of a technique in a given context. We show how these descriptions can be processed to select appropriate techniques when automatically or semi-automatically generating a 3DVE. Keywords: Information-rich virtual environments, 3D interaction techniques, Human computer interaction, Usability 1 Introduction 3D virtual environments (3DVE) are 3D user interfaces that are intended to represent geometric objects, like buildings, roads, trees, engine parts, etc. In order to perform a task in 3DVE, a user generally needs more knowledge than what is represented by 3D objects. For instance, he or she needs to know not only what an object looks like, but also what the object is, what are its properties and characteristics and how an object relates to other objects. Therefore, in addition to 3D geometry, these applications must integrate non-geometric information in the virtual environment. These environments are frequently referred to as semantically enriched virtual environments. Many types of non-geometric information can appear in such environments: simple numeric values associated to 3D objects (e.g. the heat of a part); semantic relationships between objects (e.g. “this parking lot belongs to that building”); or abstract concepts (e.g. safety instructions for operating a device). Several interactive presentation techniques have been devised to incorporate these types of information into 3DVE: Illustrative Shadows [1], Virtual PDA [2], Croquet 3D Windows [3] & Interactors [4], Interactive 2D Media Layers [5], Sidebar [6], 3D labels [7] and many more. Obviously, none of them is intrinsically better than the others in all situations. Indeed, the suitability of a technique depends on several factors such as the user profile, the current task the user is performing, the location in Human-Computer Interaction. Novel Interaction Methods and Techniques Lecture Notes in Computer Science, 2009, Volume 5611/2009, 773-782, DOI: 10.1007/978-3-642-02577-8_85 773