Virtual Pads: Decoupling Motor Space and Visual Space for Flexible Manipulation of 2D Windows within VEs

The ability to access external 2D applications from within 3D worlds can greatly enhance the possibilities of many VE applications. In this paper we present a new interaction metaphor for fast, accurate and comfortable manipulation of external GUIs displayed as texture-mapped rectangles. The main idea is to decouple the motor space from the visual space so that the external application can be manipulated within a user-defined working volume whose location and size is completely independent from the application's visual representation. This decoupling is accomplished through a virtual pad which receives user actions and maps them into cursor movements. The main advantage of our approach is that both the working space and the visual space can be adjusted independently to suit user preferences. This allows users to seamlessly balance speed and accuracy without affecting the visual representation of the application's GUI. We have implemented an interaction technique adopting our metaphor in combination with a pointing technique and we have evaluated its effectiveness in terms of task performance and user preference. Our experiments indicate that the proposed technique increases user's comfort while providing dynamic management of speed/accuracy tradeoff