3D printing is widely used to physically prototype the look and feel of 3D objects. Interaction possibilities of these prototypes, however, are often limited to mechanical parts or post-assembled electronics. In this paper, we present Capricate, a fabrication pipeline that enables users to easily design and 3D print highly customized objects that feature embedded capacitive multi-touch sensing. The object is printed in a single pass using a commodity multi-material 3D printer. To enable touch input on a wide variety of 3D printable surfaces, we contribute two techniques for designing and printing embedded sensors of custom shape. The fabrication pipeline is technically validated by a series of experiments and practically validated by a set of example applications. They demonstrate the wide applicability of Capricate for interactive objects.

We contribute Permulin, an integrated set of interaction and visualization techniques for multi-view tabletops to support co-located collaboration across a wide variety of collaborative coupling styles. These techniques (1) provide support both for group work and for individual work, as well as for the transitions in-between, (2) contribute sharing and peeking techniques to support mutual awareness and group coordination during phases of individual work, (3) reduce interference during group work on a group view, and (4) directly integrate with conventional multi-touch input. We illustrate our techniques in a proof-of-concept implementation with the two example applications of map navigation and photo collages. Results from two user studies demonstrate that Permulin supports fluent transitions between individual and group work and exhibits unique awareness properties that allow participants to be highly aware of each other during tightly coupled collaboration, while being able to unobtrusively perform individual work during loosely coupled collaboration.

Sifting and sense-making of video collections are important tasks in many professions. In contrast to sense-making of paper documents, where physical structuring of many documents has proven to be key to effective work, interaction with video is still restricted to the traditional "one video at a time" paradigm. This paper investigates how interaction with video can benefit from paper-like displays that allow for working with multiple videos simultaneously in physical space. We present a corresponding approach and system called PaperVideo, including novel interaction concepts for both video and audio. These include spatial techniques for temporal navigation, arranging, grouping and linking of videos, as well as for managing video contents and simultaneous audio playback on multiple displays. An evaluation with users provides insights into how paper-based navigation with videos improves active video work.

In this paper, we present a novel device concept that features double-sided displays which can be folded using predefined hinges. The device concept enables users to dynamically alter both size and shape of the display and also to access the backside using fold gestures. We explore the design of such devices by investigating different types and forms of folding. Furthermore, we propose a set of interaction principles and techniques. Following a user-centered design process, we evaluate our device concept in two sessions with low-fidelity and high-fidelity prototypes.

We present a device concept and a prototype of a future mobile device. By featuring a rollable display, its display size and its form factor can be dynamically changed. Moreover, we investigate how physical resizing of the display can be used as an input technique for interacting with digital contents and present a set of novel interaction techniques. Evaluation results show that physical resizing of the display can improve the way we interact with digital contents on mobile devices.

Increasingly powerful mobile devices like the Apple iPhone empower learners to watch e-lectures not only at home but also in mobile learning scenarios virtually anywhere and anytime. However, state of the art mobile video browsers do not support learners in getting an overview on and navigating between the large amounts of semantically related e-lectures, which are available in various digital libraries. We contribute a novel user interface for the mobile use of e-lectures. Leveraging a spatial navigation metaphor, it supports both linear and nonlinear interaction within a single lecture, as well as the efficient navigation within large e-lecture libraries. Evaluation results show that our e-lecture browser significantly improves the learning process and leads to significantly higher efficiency and user satisfaction.