G-raff: An Elevating Tangible Block for Spatial Tabletop Interaction

CHI 2015, April 18–23, 2015, Seoul, Korea – Note presentation


Chang Min Kim, Tek-Jin Nam


We present an elevating tangible block, G-raff that supports spatial interaction in a tabletop computing environment. The elevating head part of G-raff moves according to the given height and angle data. We adopted two rollable metal tape structures to create large movements with a small volume block. On the head part, a smartphone can be mounted either horizontally or vertically. G-raff becomes a device that can connect a mobile device with a tabletop computer, thus a new spatial representation and control interaction is made. This paper introduces the design details, key features and applications of G-raff. We report on the results of a preliminary user study and discuss future work to improve the elevating device. This work contributes to maximizing the availability of augmented reality space above the tabletop display.


Tangible interface; spatial interaction; interface devices

ACM Classification

H.5.2. User Interfaces: Input devices and strategies