A Tangible Volume for Portable 3D Interaction

TL;DR

The paper tackles portable, natural 3D manipulation without external monitors by introducing a tangible volume—a handheld, screen-covered object that displays a portion of the virtual scene through its surfaces. It combines a grasping manipulation metaphor with fish-tank rendering and inside-out tracking, and evaluates usability through two user studies and a partial prototype. Key contributions include the tangible volume concept, a grasp-based selection method, empirical evidence on intuitiveness and field-of-view effects, and a discussion of extending interactions through the volume surface. This approach advances portable 3D interfaces with potential across visualization, prototyping, and gaming.

Abstract

We present a new approach to achieve tangible object manipulation with a single, fully portable and self-contained device. Our solution is based on the concept of a "tangible volume". We turn a tangible object into a handheld fish-tank display. The tangible volume represents a volume of space that can be freely manipulated within a virtual scene. This volume can be positioned onto virtual objects to directly grasp them, and to manipulate them in 3D space. We investigate this concept through two user studies. The first study evaluates the intuitiveness of using a tangible volume for grasping and manipulating virtual objects. The second study evaluates the effects of the limited field of view on spatial awareness. Finally, we present a generalization of this concept to other forms of interaction through the surface of the volume.

Figures (10)

• Figure 1: Manipulation issues that arise when a typical mobile device is used as a tangible handle:  (a) the virtual object does not rotate about its own center;  (b) the virtual object leaves the field of view;  (c) when trying to reduce the distance to avoid the above issues, the virtual object is clipped.
• Figure 2: Illustration of our concept of a "tangible volume". Part of a larger virtual scene can be seen through the tangible object held by the user. On the top right, the tangible volume is observed from a different angle. On the bottom right, the tangible volume has been translated in space and now encloses a different part of the virtual scene.
• Figure 3: Illustration of the different steps of object manipulation in our interface concept. First, the tangible volume is positioned onto a virtual object. To disambiguate between nearby objects, an outline indicates which object is both inside the volume and closest to its center. This object can be grasped by pressing the fingers on the volume. The object is then attached to the volume, and can be directly moved alongside the volume in 3D space. The object is detached when finger pressure is released. If virtual gravity is enabled, it then falls to the ground.
• Figure 4: A partially simulated implementation of our concept, using augmented reality. A physical cube serves as the tangible volume. We covered its faces with six pressure sensors, then with AR markers. A tablet, raised to eye level, turns the markers into virtual screens. Users manipulate the cube by looking through the tablet, as if they were directly holding the real device.
• Figure 5: View of the electronic components inside the cube. The embedded microcontroller retrieves values from the pressure sensors on the cube surface, and sends them to the rendering software on the tablet through a wireless connection.