Space is an essential part of social communication. The distance individuals choose when communicating with each other conveys non-verbal information and social signals. In remote, audiovisual communication, though, spatial information is hardly considered in the technical set-ups, often arbitrary and unequally perceived by the participants. In this article, we describe an audiovisual communication system that takes distance into account. Based on a display equipped with depth sensors, we divide the space into different zones and use human position in the room to enable interaction between remote participants. This way, the physical availability of a communication partner is imitated and distance between individuals can be used naturally to convey non-verbal information in remote set-ups.

An ethnographic study reveals how professional artists created a spectator interface for the interactive game Day of the Figurines, designing the size, shape, height and materials of two tabletop interfaces before carefully arranging them in a local setting. We also show how participants experienced this interface. We consider how the artists worked with a multi-scale notion of interactional trajectory that combined trajectories through individual displays, trajectories through a local ecology of displays, and trajectories through an entire experience. Our findings shed light on discussions within HCI concerning interaction with tangible and tabletop displays, spectator interfaces, ecologies of displays, and trajectories through cultural experiences.

This is a short presentation of a uniform approach for specifying mixed reality user interfaces, including 3D interaction techniques and 3D widgets. Our main goal is to facilitate the process of reusing previous work, so more complex applications can be built and documented in a formal and uniform way. We describe here the conceptual model of user interface components, which allows us to generalize user interface components and to port them to different hardware settings and application contexts. An XML-based specification language implements the conceptual model and allows for automatic processing and tool support.

Augmented Reality (AR) technologies are rapidly expanding into new application areas. However, the development of AR user interfaces and appropriate interaction techniques remains a complex and time-consuming task. Starting from scratch is more common than building upon existing solutions. Furthermore, adaptation is difficult, often resulting in poor quality and limited flexibility with regard to user requirements. In order to overcome these problems, we introduce an infrastructure for supporting the development of specific AR interaction techniques and their adaptation to individual user needs. Our approach is threefold: a flexible AR framework providing independence from particular input devices and rendering platforms, an interaction prototyping mechanism allowing for fast prototyping of new interaction techniques, and a high-level user interface description, extending user interface descriptions into the domain of AR. The general usability and applicability of the approach is demonstrated by means of three example AR projects.

The availability of a suitable framework is of vital importance for the development of Augmented Reality (AR) and Virtual Reality (VR) projects. While features such as scalability, platform independence, support of multiple users, distribution of components, and an efficient and sophisticated rendering are the key requirements of current and future applications, existing frameworks often address these issues only partially. In our paper we present MORGAN --- an extensible component-based AR/VR framework, enabling sophisticated dynamic multi-user AR and VR projects. Core components include the MORGAN API, providing developers access to various input devices, including common tracking devices, as well as a modular render engine concept, allowing us to provide native support for individual scene graph concepts. The MORGAN framework has already been successfully deployed in several national and international research and development projects.