| 3D reconstruction of engineering view is an important research topic in computer aided design.Automatic recognition and understanding based on engineering view has become an important development direction of the science and intelligent manufacturing of artificial intelligence.Three dimensional reconstruction technology is one of the research difficulties in the field of computer graphics and computer vision.As an important means of geometric modeling,three-dimensional reconstruction automatically completes the transformation from two-dimensional engineering view to three-dimensional model,and builds a bridge between three-dimensional model and two-dimensional graphics.It has important practical significance in the field of engineering technology,and is an important technology for the realization of intelligent and automatic engineering design.This paper studies the 3D reconstruction technology of engineering view,analyzes the problems of existing reconstruction and recognition algorithms and the limitations of application,proposes a recognition algorithm based on basic body model guidance,designs an effective scheme,and completes the 3D shape recognition and reconstruction of engineering view.The main work of this paper is as follows:(1)This paper introduces the three view projection features and projection matching relationship of basic bodies.By analyzing the projection features of common engineering views,two basic body types of extrusions and rotations are added as the content of basic body knowledge base.(2)In order to solve the problem of missing basic body projection information in engineering view,the preprocessing algorithms such as graph splitting and automatic line filling are proposed.The search strategy with specific priority order is formulated to find the effective projection closed loops of different basic bodies on the feature view.According to the projection rules corresponding to the constraint relationship and the engineering view,the corresponding projection graphics of the closed loops on the other views are obtained.By comparing the projection features of the basic body knowledge base,the recognition of basic body types is realized,and the geometric parameters of basic bodies are extracted and the data is stored.(3)Based on the realization of single class basic body recognition,a recognition algorithm is proposed to judge the spatial position relationship between basic bodies by projection information,and then determine the Boolean operation type and combination relationship between basic bodies.By using basic body data and Boolean operation,the CSG tree of composite body is constructed automatically,and the 3D reconstruction and expression of composite body are realized.In this paper,the DXF format engineering view is used as the data source of information recognition,and the above algorithm is programmed in the VC++ 6.0 development environment by using C++ language and Open GL function library tools.The feasibility and practicability of the three-dimensional reconstruction algorithm are verified through a large number of test examples. |
