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. 

We here present 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 dierent stories depending on the Point of View adopted and support dynamic modification of the story world which results in different story consequences.

Comparison of narrative variants obtained by generating the pound-of-flesh subplot with different PoV (left side (pov antonio-risk-taker), right side (pov shylock-victim)).
Key constraints selected by the generator run down the centre with the selected narrative actions for each PoV to the sides of the constraints.

A single generated narrative that switches PoV from (pov antonio-risk-taker) to (pov shylock-victim) and back to (pov antonio-risk-taker). 
Key constraints selected by the generator are highlighted (A1, C1, S1, S2, C2, C3, A2) and are preceded by the sequences of narrative actions selected for those constraints. 

Merchant of Venice (1) - Antonio Risk Taker

Merchant of Venice (2) - Shylock Victim