Head-mounted displays (HMDs) based augmented reality (AR) systems have been applied for design simulations. Although such AR systems give users 3D and real scale feelings of digital data that could be useful in design explorations, there are a few practical uses because most of the AR systems provide just visualization. Even though users come up with a new design through the visualization, there are few ways to create a new design or modify the current design in the AR systems. For adding such functions to AR systems, we propose a new tangible user interface for AR systems called "AR-Jig".
AR-Jig is a handheld tool to modify a curve on a digital 3D model by manipulating physical in-line pins of the tool. Once a user selects a target curve, it sticks to the pins' heads. The movability of the device allows for flexible access to digital 3D data represented in the AR systems. Then the user can control the digital curve (and the surrounding surface) through physical manipulations. The physical form allows users to modify digital 3D data without going back to desktop systems. In addition, the computer can modify the curve by actuating the pins with motors according to some calculations about the model such as size limitations, element layout conditions, and so on. Haptic feedbacks by the actuated pins convey the computer's suggestions to the user. AR-Jig allows the user and the computer to find a better curve through tangible collaborations/negotiations. While the physical form is not enough to represent all the digital data, virtual views through HMDs allow the users to perceive all the digital 3D data.
Although the target of AR-Jig is complicated 3D data, the structure is still simple. This simple physicality keeps the merits of tangible user interfaces, which are direct, intuitive, and simultaneous manipulations. The direct hand manipulation of AR-Jig is easy to use with HMDs. The intuitive pin manipulation gives an idea to capture a physical contour by pushing the pins against it. The simultaneous multi-pin manipulation lets users control points on a curve quickly. At the same time, AR-Jig also gives the merits of digital user interfaces because of pin actuation, flexible mapping between physical form and digital data, and AR views. The actuation enables numerical manipulations of the pins by using 10 keys on the device. The flexibility enables multi selection and global control of digital data by the local physical manipulation. AR views support data scale changing so that control resolution can be changed. AR-Jig is an interface between simple physicality and complex digitality as well as between human and computer.
(Source: http://tangible.media.mit.edu/projects/ar-jig/)