Grab-and-Throw Metaphor: Adapting Desktop-based Interaction Paradigms to Virtual Reality

The drag-and-drop metaphor is one of the most common direct interaction metaphors used in desktop-based environments. This direct interaction paradigm enables an intuitive method to apply actions by associating iconic representation of objects to each other. Since dragging of these iconic representations is the most time-consuming subtask of the dragand- drop metaphor, many extensions of this approach have been proposed to enhance this process. However, a transfer of these concepts to virtual reality (VR) systems has not been realized. In this paper we propose the grab-and-throw metaphor which is a VR-based analogon to the drag-and-drop metaphor. The proposed concepts enable users to select a virtual object by grabbing it and to throw the object within a virtual environment (VE) in the direction of another object. As soon as the object hits another object, an associated action is performed. The trajectory of the thrown object is based on physical motions adapted from the real-world. In order to ease hitting a desired target object, snapping strategies are used such that the aimed object attracts the thrown object. We give a technical description of the grab-and-throw metaphor and discuss example application scenarios which benefit from the usage of the described metaphor.