Exploring Structural Morphology Using CAD

Often in the design process the student's imagination is restricted by their inability to visualise, model or accurately sketch ideas for innovative structural systems. By using CAD as a design tool it is possible to explore the morphology of complex structures and to be able to produce perspective drawings of them with relative ease. Within AutoCAD there is a small library of standard three-dimensional objects and surfaces that can be called upon to generate more complex forms. However, to further facilitate the architectural design process, an extended library of innovative structural forms would allow the professional designer, or student, greater design freedom and any increase in the palette of structural forms available should stimulate creativity. As practical examples, the paper describes how students have been encouraged to experiment with the use of structures which can only be physically modelled with difficulty and which are also difficult to represent on the two- dimensional surface of the drawing board unless the geometry has previously been determined by the methods described. These are (i) Reciprocal Frame three-dimensional beam grillage structures and (ii) plate domes created from lattice structures by point-to- plane duality. The problem, of representation of these structures has been overcome, in the first case, by generating AutoLISP procedures to draw the complex three-dimensional geometrical form automatically in AutoCAD and, in the second case, by the development of the computer program CADual