Applying a Plan-Recognition / Plan-Generation Paradigm to Interactive Storytelling

A key issue in interactive storytelling is how to generate stories which are, at the same time, interesting and coherent. On the one hand, it is desirable to provide means for the user to intervene in the story. But, on the other hand, it is necessary to guarantee that user intervention will not introduce events that violate the rules of the intended genre. This paper describes the usage of a plan recognition / plan generation paradigm in LOGTELL, a logic-based tool for the interactive generation and dramatization of stories. We focus on the specification of a formal logic model for events and characters' behaviour and on how the tool helps the interactive composition of plots through the adaptation of fully or partially generated plots. Based on the model, the user can interact with the tool at various levels, obtaining a variety of stories agreeable to individual tastes, within the imposed coherence requirements. The system alternates stages of goal inference, planning, plan recognition, user intervention and 3D visualization. Our experiments have shown that the system can be used not only for entertainment purposes but also, more generally, to help in the creation and adaptation of stories in conformity with a specified genre.