A Collaborative Virtual Workspace For Visual Expression - CiteSeerX

Tagtool: A Collaborative Virtual Workspace For Visual Expression Thomas Pintaric∗1 , Markus Dorninger†2 , Mathis Csisinko1 , Josef Dorninger2 , Ferdinand Pilz1 , Matthias Fritz2 , and Martin Norden1 1

Attentive GmbH 2 OMAi GmbH late 18th and 19th century, magic lantern performances employed a combination of moving projections, storytelling, and live music to entertain, educate, and enchant audiences. In Japan, the use of portable wooden lanterns allowed multiple Utsushi-e performers to deliver carefully synchronized visual performances [Willis 2012].

Figure 2: A 19th century Japanese Utsushi-e performance. Figure 1: A collaborative virtual puppeteering performance using Tagtool on two networked tablet computers.

Abstract

Since the advent of digital projectors, which first appeared in the 1980s, projection art has undergone a renaissance that has spawned a variety of interactive systems geared specifically towards visual improvisation. Tagtool carries on this legacy and enriches it with modern multi-touch interaction techniques.

Tagtool is a distributed system for collaborative visual expression. Its fundamental premise is rooted in the duality of painting and animation, enabling multiple users to simultaneously create images and bring them to life. Use cases include site-specific projection art, spontaneous visuals to music, and improvised animated narratives. Using wirelessly networked tablet computers running the Tagtool software, an ensemble of visualists performs in a shared virtual workspace. Tagtool emphasizes free-flowing interaction between the artists and the environment. The system is optimized for use with digital projectors, allowing the images to escape from the tablet screen and emerge as immersive visuals on real-world structures. The portable form factor of multi-touch tablets combined with the possibility to wirelessly stream interactive graphics between devices and displays open up new possibilities for staging art performances. Tagtool’s user interface is based on insights gathered from comprehensive interviews with artists around the world. The resulting design aims to avoid the linear workflow of established desktop user interaction metaphors. Instead, it makes extensive use of multitouch interaction - allowing for all ten fingers to be used concurrently in fluid and expressive manipulations like those performed by musicians.

Introduction Contemporary projection art traces its technological roots back to the 17th century Laterna Magica. Peaking in popularity during the ∗ [email protected] † [email protected]

Figure 3: Close-up of the Tagtool user interface.

System description Tagtool differs from existing systems for digital storytelling, such as [Russell 2010] in several significant ways: • Real-time collaboration between multiple users is an integral part of Tagtool. • We deliberately make no distinction between authoring and presentation modes. Everything that is created is simultaneously presented live. • For its basic functions, Tagtool relies extensively on gestural (multi-touch) controls, avoiding the linear workflow constraints of established desktop user interaction metaphors. A number of systems, such as [Willis et al. 2011] use the physical movement of a portable pico-projector to create virtual character

Figure 4: A typical Tagtool setup.

interactions. However, it is not quite clear how this metaphor could be extended to control multiple characters simultaneously, or to allow for more complex, layered interactions. In Tagtool, virtual characters are not tied to a physical output device. As illustrated in figure 4, a typical Tagtool setup consists of multiple (currently up to eight) off-the-shelf tablet computers and a single digital projector (either connected wirelessly or plugged into one of the tablets). At the beginning of a performance, users join a shared workspace. Tagtool automatically discovers other devices on the same wireless LAN using zero-configuration networking. It is possible for users to leave or join an ongoing session at any time. All paintings and animations are continuously synchronized among all participants at runtime. The fundamental operations of Tagtool are painting and animation. Users can paint with multiple fingers and typically use their nondominant hand to modulate size, shape, and color of brush strokes. An aiming aid is provided to indicate the brush position in an external projection before starting to draw a stroke. This helps artists with mapping their artwork to features of real world structures, creating immersive animated environments. At any time, graphical layers can be moved, rotated or zoomed with multi-touch gestures. Layers exist in a 2.5D universe and can be arranged across the Z-axis to allow for virtual staging of characters and environments. Through hierarchical grouping of layers, users can create increasingly complex animated scenes.

Conclusion Tagtool is still very much a work in progress. Even in its first initial revision, however, we were able to successfully deploy our system in a variety of applications contexts. Among them are digital storytelling, education, audiovisual performances, digital heritage (projecting on architectural monuments and artifacts) and street art culture.

Figure 5: Improvised street art performance using Tagtool.

ence on Tangible, embedded, and embodied interaction, ACM, New York, NY, USA, TEI ’10, 271–274.

References

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