Building a Design Family: Explicit Support for Contingency Handling and Exploratory Design in Multimedia Authoring

Multimedia presentations are often intended to cater for a wide range of viewing scenarios, encompassing variety with respect to factors including the delivery platform, audience experience level and individual reader preferences. Existing presentation-building tools either make no provision for such variation, or go some way by providing generic information structures that are interpreted at the time of information delivery to produce a supposedly appropriate presentation. For the moment, at least, this latter approach has severe limitations, simply because no tool designer yet has su cient experience in multimedia communication to de ne generic structures that will serve a suitable range of presentation intent and readers' needs. This report proposes an authoring approach that avoids these limitations, by explicitly recognising the authoring task as the creation of a family of designs. Building their presentations in a constraint-based environment that directly represents the design family will help authors to deal with the full complexity of delivery variation, and to keep track of whether all predicted viewing scenarios are supported satisfactorily. At the completion of the project in which this work was undertaken, the authoring environment had not yet been demonstrated. The report documents the design and implementation work that was done, and includes suggestions as to how the ideas can be developed further.