Authors : Hamid Haghshenas Gorgani, Iman Magh Soudi Neyestanaki and Alireza Jahantigh Pak
Abstract: By knowing this fact that 2D engineering drawings which are impartible component of today design and manufacturing processes cannot be used directly as input of CAD/CAM systems and their editing is difficult it is necessary to reconstruct 3D solids from them. This process usually performed by two approaches: B-Rep (Boundary representation) and CSG (Constructive Solid Geometry). Each of these approaches have strengths and weaknesses. In this study, however represented algorithm is not exactly based on B-Rep or CSG approaches but mostly lies on CSG. This process consists of outer pattern recognition in each orthographic view by use of a mathematic algorithm regarding to real and virtual vertices then extrusion of these patterns and making subscripted solid from obtained extruded volumes. At the next step, inner patterns of each view which are straight or curved lines are extruded and some faces are obtained which fractionalize the volume of previous step into smaller volumes. The final solution is a subset of these volumes therefore an arbitrary subset is selected and orthographic views of result volume are generated. These orthographic views are compared with initial orthographic views. The process of selecting subsets, generating orthographic views and comparing views is continued until find complete conformity between views. Also, it is clear that, existence of answer without any vagueness is assured. One of advantages of this method is that finding solution volume is certain. This solution unlike B-Rep method has no vagueness and for as much as can cover all non-geometric volumes, one of the most important weaknesses of CSG method which is its limited domain is removed.
Hamid Haghshenas Gorgani, Iman Magh Soudi Neyestanaki and Alireza Jahantigh Pak, 2017. Solid Reconstruction from Two Orthographic Views Using Extrusion and Comparative Projections. Journal of Engineering and Applied Sciences, 12: 1938-1945.