Graphical Modelling with Computer Extended Descriptive Geometry (CeDG): Description and Comparison with CAD

Abstract

We present a Computer Extended Descriptive Geometry (CeDG) approach for modelling spatial geometric systems that surpasses several CAD limitations. A first concept proof has shown that the CeDG can be implemented on the dynamic geometry software (DGS) paradigm to generate parametric models based on descriptive geometric techniques. Thereliabilityandperformanceofthe CeDG approachwascomparedto CAD throughtwo study cases from the sheet metal and mechanisms design fields. The outcomes demonstrate that CeDG is able to compute the design geometrical parameters concurrently with the modelling process and to obtain planar cutouts of 3D surfaces, in situations where CAD systems can not do it. The implementation was performed in Geogebra© for CeDG and Solid Edge© 2009 for CAD, which were selected because of their cutting edge technology. As main conclusion, the CeDG approach is a Descriptive Geometry (DG) - based computer parametric graphical modelling that may complement the CAD technology with accuracy and reliability.