Automatic generation of parametric drawings using DXF and Visual Basic

1 Alcínia Zita Sampaio, Technical University of Lisbon, Dep. Civil Engineering and Architecture, [email protected] 2 António Aguiar da Costa, Technical University of Lisbon, Dep. Civil Engineering and Architecture, [email protected] Abstract The definition of drawings based on parametric shapes is a fast way to create similar drawings. In technical fields, such as Civil Engineering, the elaboration of design documentation involves a great number of drawings that are identical in configuration, the values of some of the dimensions the only changes that need to be made. It is, then, important for engineering students to know how to implement software that could help to obtain, quickly, the same kind of drawings needed in projects of a specific area in engineering. Among examples of this type of drawing are: the cross section of a column, the details of the iron reinforcements in a slab or the section of a metal beam. This subject was introduced into the undergraduate Civil Engineering curriculum as part of the Computer Aided Drawing course. With this module the students acquire knowledge about a type of drawing format file, DXF, which is frequently used as an integral part of several engineering computer applications. The data structure is presented and they learn how to define drawings, directly writing files following the specific DXF data structure. They use the Visual Basic language to develop small computer programmes to allow the generation of basic technical drawings. This programming language has a friendly interface which is very easy both to understand and to use. The students first elaborate the automatic generation of lines and circular arcs and then develop their own application. The paper shows the most relevant aspects of the teaching process and some results obtained by the students.