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

Abstract

Serial plates are not reasonable in material saving and stress dispersion. To design orthopedic plates ideally and conveniently, this paper proposes a method to optimize plates through editing semantic parameters based on average bone model. Firstly, for the reasonable distribution of serial plates in number and size, an average bone model is created from the existing bones, among which each bone has a contribution to the average model. Secondly, a common orthopedic plate with semantic parameters is constructed on average bone model and it can be conveniently modified. Lastly, optimizing the thickness of the plate through finite element analysis and genetic algorithm to meet the stress condition and use as little material as possible. The simulation results indicate that the method can save material and disperse the stress of the plates so that it can effectively optimize the orthopedic plates.

Comparison of Computer Extended Descriptive Geometry (CeDG) with CAD in the Modeling of Sheet Metal Patterns

“…CEDG approach. The spacial hopper was obtained using descriptive geometry procedures in agreement with the CEDG foundation [20]. The intersection of the main cylinder with the upper conical surface is computed using the technique of auxiliary planes containing generatrix lines [24] and extended by the mathematical locus function.…”

“…In opposition to the well-known LogiTRACE and Solid Edge CAD approaches, CEDG is a very novel technique [20] that needs a deeper and comprehensive description. This is presented in the Supplementary file.…”

“…The Computer Extended Descriptive Geometry (CEDG) is a novel approach for the parametric modeling of 3D geometric systems [20]. It is founded on descriptive geometry techniques, and it must be implemented in a Dynamic Geometry Software (DGS).…”

“…It is founded on descriptive geometry techniques, and it must be implemented in a Dynamic Geometry Software (DGS). Geogebra is a widely spread DGS [21] selected in this study to implement CEDG [20].…”

“…No geometrical requirements are needed, excepting that the surfaces are developable. The CEDG could be extended to include additional algebraic objects that automate the modification of the pattern drawing according to material and forming process requirements [20]. We are interested in comparing the reliability and accuracy of CEDG and CAD approaches in the computation of patterns' drawings that do not depend on the manufacturing process.…”