A language for defining spatial trusses

Abstract

This paper describes a computer language enabling its users to define three-dimensional truss structures. The language can be used either as a design tool in specifying the geometrical characteristics of these structures or as an input language to a program that actually performs their structural analysis. The main characteristic of the language is that it is procedural; programs defining a nucleus of a structure can be made into procedures (subroutines) which can be called within programs and other procedures in order to define more complex structures composed of that nucleus or its variants. This characteristic is particularly useful in defining repetitive geometrical patterns which themselves appear within repetitive patterns. The paper also describes a syntax-directed compiler whose input is a sentence in the language and whose output is interpretable code which, when executed, produces drawings and provides listings of the coordinates of the points and the linkages defined by the user in his source program. Several examples of structures defined using this language are included in the paper.