【作者】 王晶晶；

【导师】 夏禾； 陈岱林；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 当代计算机软、硬件技术的迅猛发展为开发新一代桥梁CAD软件提供了技术保障。本文针对桥梁CAD技术应用现状和日益发展的软件技术,对桥梁CAD软件开发技术进行了系统研究,开发了一套基于自主知识产权的PKPM3D图形平台的应用虚拟现实技术的桥梁构件参数化建模系统——城市立交桥虚拟现实系统,具体的研究工作包括:(1)图形平台在CAD系统中占有极为重要的地位,故本文着重研究了具有自主知识产权的PKPM3D图形平台的二次开发特性,论证了其可以替代通用的图形平台AutoCAD作为二维和三维CAD软件系统的图形平台的可行性。(2)探讨了增强立交桥三维模型逼真度的方法。采用基于几何建模和图像建模相结合的混合建模技术创建立交桥三维模型和虚拟场景;运用纹理映射技术和虚拟漫游方式增强虚拟场景的沉浸感。(3)研究桥梁的结构和设计特点,以模版参数化设计为指导,运用现代编程技术,创建了可扩充的桥梁构件模版库,并运用ACCESS创建了可导出的桥梁构件数据库,还利用MFC和平台类库设计并开发了桥梁参数化建模窗口模块、桥梁附属物模块和虚拟漫游模块,最终再加载道路模块,完成了以PKPM3D图形平台和ACCESS数据库为支撑的城市立交桥虚拟现实系统,填补了国内基于自主知识产权平台开发桥梁三维建模软件的空白。(4)根据实际工程对软件性能进行测试,论证了桥梁构件模版参数化建模方法的切实有效性,大大缩短了建模时间,提高了设计效率。更多还原

【Abstract】 The prompt development of modern software & hardware technology provides us with advantage to develop a new generational bridge CAD system. On the basis of the current states of bridge CAD application and the rapid development of software technology, this paper studies systematically on the software development technology of bridge CAD system, and develops a Virtual Reality System for Urban Overpass Bridges, which is based on the PKPM3D graphical platform of independent intellectual property. This system takes bridge component parametric modeling as the modeling method, and uses virtual reality technology. The study includes:(1) Since graphical platform plays an important role in the CAD system, the paper studies the secondary development characteristic of PKPM3D graphical platform which is of independent intellectual property. And it proves that it is feasible for PKPM3D to take the place of universal graphical platform AutoCAD as 2D or 3D CAD system’s developing platform.(2) The approach to enhance the fidelity of the virtual overpass scene is discussed. A combination of geometric-based modeling and image-based modeling technology is used to create the model of the overpass. Texture mapping algorithm and Virtual roaming technique is used to increase the scene fidelity.(3) In the first place, structure and features of bridge is researched, using the design of parametric templates as a guide and applying the modern Programming techniques to create a template library of bridge components which can be expanded. And then a library of bridge components which can be derived is created. Besides, design and develop the windows for bridge parametric modeling module, bridge accessory module and virtual roaming module using MFC and the platform class library. Finally, after the road module is loaded, a Virtual Reality System for Urban Overpass Bridges is accomplished, which is supported by PKPM3D graphical platform and ACCESS database. It fills the gap in China in the field of bridge 3D modeling software which is based on graphical platform of independent intellectual property.(4) According to real project, the software feature is tested. This work proves that parametric modeling method for bridge components is really effective. This method shortens the modeling time and improves the efficiency of design work.更多还原