3D Solid Reconstruction Based On 2D Orthographic Drawings

For a long time, the question of reconstruction of 3D solid objects from 2D orthographic views has been an important research direction in both the technology of computer aided design/ computer aided made(CAD/CAM) and C&G fields. In this paper, the current problems and characteristics in three dimensional shape reconstruction and the structure characteristics of AutoCAD's Solid Modeling System are invested. Rely on the advanced programming language VC++, this paper brought forward a method of 3D reconstruction by using ObjectARX2000 to develop AutoCAD. The realization of this algorithm mainly used many classed and functions of ObjectARX. Then the program was compiled in the environment of VC++6.0. In the end the ARX application was created. When this application was load in AutoCAD, this 3D reconstruction function can be usable. Concrete algorithm is firstly recognizing 2D feature obtained from geometric entities, then on the instruction of the shape analysis combining with the projective rulers of mechanical drawing, matching three 2D view features, creating 3D basic model, forming a operation list, finically finished 3D reconstruction. It proves in practice the effectiveness and fruiti'iess of the approaches. There are five chapters in this thesis.Chapter 1 shows the current development conditions of CAD/CAM. It also discusses the significance of research 3D reconstruction on AutoCAD system, and the research work of the current methods is addressed. Finally, it outlines a new approach, which is gonging to be presented in this paper.In Chapter 2, some basic knowledge and rulers on mechanical drawing are reviewed, and the computer of two dimensional view features is introduced. An automatic recognizing method of 2D view feature based on ObjectARX in AutoCAD is presented. Through recognizing and matching 2D view feature to construct 3D solid, consequently it gets ready for transforming from 2D to 3D. Chapter 3 firstly introduces the basic theory of Solid Modeling system generally, and then elaborates on 3D solid's all kinds of descriptive modes in computer inside. On the basis of this it analysis the technology of AutoCAD's solid modeling system. In the end some previous research works in 3Dreconstruction is investigated.In Chapter 4, we are gong to depart three orthographic views drawing interactively. When we finished 2D view features' recognized we math three corresponding orthographic views drawings. The shape parameters and location parameters are obtained. So the 3D basic model can be created from these parameters. These models form a operation list, use Boolean operation. Finically finished 3D reconstruction. To do this we also need to build a feature library with it the application can know what features can create what model. We develop a AutoCAD command to execute all reconstruction work.In Chapters, we do a reconstruction experiment. A three orthographic views AutoCAD drawing is a input, we could use command "3d" to acquire the solid model of input. Charts explain this process main. In addition, we give other examples to show this.