On the representation and generation of loosely packed arrangements of rectangles

Several computer programs that enumerate rectangular dissections as solutions to certain layout problems have established a distinct paradigm for dealing with the crucial theoretical issues involved. In the present paper an extension of the paradigm is suggested, to include 'loosely packed arrangements of rectangles', which arc of wider applicability in an architectural context. Orthogonal structures are introduced to represent these arrangements and the conditions of well-formedness for these structures are established. A grammar to enumerate orthogonal structures is presented and it is suggested that best use is made of the grammar if it is incorporated into a generative expert system, able to serve as a vehicle to discover, encode, and utilize a broad range of constraints and criteria in the generation of layout alternatives.