Notes on the Use of Plan Structures in the Creation of Interactive Plot

An interactive system defines a virtual space, whether the system’s interface provides access to the inhospitable planet of Stroggos or the Microsoft Windows desktop. Users of both these systems interact with a place, one created by a computer and in which users and computational agents carry out their individual and collective activities. The intuitive and often-discussed benefit of a well-designed interface metaphor is that it allows users to carry over conventions from their "real" experience when performing tasks within the interface world. Another key and often unarticulated value of an interface arises from the interface’s mimetic quality. While mimesis is often discussed by narrative theorists as a contrast to diegesis, distinguishing the concepts of showing versus telling (Aristotle), my emphasis here is to distinguish between an artifact that is intended to be an imitation of something, but is not really that thing and an artifact that is intended to be mistaken as that thing. An example of the former case would be a film of a fictional account of the D-Day landing on the beaches of Normandy. An example of the later might be a virtual reality system displaying photo-realistic graphical images of a physical space. D-Day stories like The Longest Day and Saving Private Ryan are, in some ways, imitations, and so are more mimetic than VR systems whose design is intended to "...produce synthetic images visually and measurably indistinguishable from real world images." (Greenberg 1999)(pg. 45). The interface to a virtual space presents an abstracted, artificial representation of a world and the activities within it; it is the mimetic character of the space, together with our understanding that we are interacting with a mimetic artiflcat, that allows us as users to bring to bear all our knowledge of narrative understanding during our interaction (Brannigan 1992). When a user enters into a such a virtual space, it is as if a narrative contract is established between the user and the system’s authors. 1 The contract establishes