Narrative generation through characters' point of view

Virtual Actors are at the heart of Interactive Storytelling systems and in recent years multiple approaches have been described to specify their autonomous behaviour. One well known problem is how to achieve a balance between the characters’ autonomy, defined in terms of their individual roles and motivations, and the global structure of the plot, which tends to emphasise narrative phenomena and the coordination of multiple characters. In this paper we report a new approach to the definition of virtual characters aimed at achieving a balance between character autonomy and global plot structure. Where previous approaches have tended to focus on individual actions our objective is to reincorporate higher-level narrative elements in the behaviour of individual actors and address the relation between character and plot at the level of behaviour representation. To this end we introduce the notion of a characters’ Point of View and show how it enables a story to be described from the perspective of a number of different characters: it is not merely a presentation effect it is also a different way to tell a story. As an illustration, we have developed an Interactive Narrative based on Shakespeare’s Merchant of Venice. The system, which features a novel planning approach to story generation, can generate very different stories depending on the Point of View adopted and support dynamic modification of the story world which results in different story consequences. In the paper, we illustrate this approach using example narratives generated using our fully implemented prototype.