现代路线CAD系统关键技术研究与应用

【作者】 蒲浩；

【导师】 詹振炎；

【作者基本信息】 中南大学 ， 道路与铁道工程， 2002， 博士

【摘要】 本文综合应用计算机图形学、计算几何及几何造型学、科学计算可视化、人机交互、虚拟现实、计算机动画等理论和技术，针对现代路线CAD系统中的数字地面模型、路线交互设计、路线三维实体造型、路线三维模型简化、真实感图形绘制及路线三维场景的实时动态显示等关键技术进行了深入细致的研究。通过深入剖析二维平、纵、横设计与三维可视化设计之间的关系，论述了二者不是互相取代、此消彼长，而是互为补充、相辅相成的关系，应紧密结合、综合运用。基于这一思想，本文紧紧围绕二维与三维相结合的设计理论和方法展开研究，既注重了对传统的二维平、纵、横设计方法的改进，又注重了三维可视化、虚拟现实等新技术的研究与应用，主要研究内容及研究成果如下： 1)基于Delaunay及约束Delaunay三角网理论，提出并实现了适合于铁路和公路选线设计的三角网快速整体构建算法。该算法采用整体建网技术，针对海量地形数据，无需预先分块处理，能一次性构建整体连续无缝的带状三角网，避免了分块处理的接边问题，建网速度在PⅡ微机上达到了40000～45000个三角形／秒，并且考虑了地形特征线的影响，具有一次处理的点数无上限，整体连续无缝、速度快、网形优、精度高、用途广的特点，在生产中广泛应用，迄今为止，已完成了超过2000公里的铁路和近千公里的公路设计。 2)针对以往路线CAD系统平、纵、横设计分离的弱点，提出了将线路的平、纵、横断面及三维透视集成于同一界面下进行一体化设计的新方法，实现了平、纵、横的交替设计和关联设计，并提供了丰富的信息查询功能，使设计者在从事平、纵、横某一方面的设计时，可以兼顾其它两个方面，据此开发的CAD系统既保留了平、纵、横之间的相对独立性，更注重三者之间的相互关联，因此也更符合路线设计的特点。 3)提出了基于分割—归并思想的边界表示法解决了路线三维实体的造型问题，将路线这一复杂实体划分为若干要素子实体，分别研制了各子实体的三维实体造型方法完成各自的造型，然后将各子模型拼合成整体。应用约束Delaunay三角网理论研制出的“三角网裁剪”算法成功地解决了拼合计算的难题，使拼合计算过程大为简化，提高了建模的速度和精度。 4)由于路线三维实体模型的复杂性，使得对这一场景的计算、显示及存储均要耗费巨大的时间和空间，这使得我国以往在道路三维可视化技术方面的研究只能停留在最终设计成果的表达上而难以融入设计的过程中，为此，本文从路线三维模型的简化技术入手，深入研究了路线三维实时动态显示的理论与方法。 博士学位论文 提出并实现了一种行之有效的路线三维模型的视点相关简化算法，该算法重点解决路线三维场景中最复杂的两个要素：地形模型和设计线模型的简化问题。实践验证，该算法能在保证模型具有较好的视觉效果的前提下，大大降低模型的复杂度，并且具有较高的执行效率，为进一步研究模型的动态实时显示技术奠定了基础。 5）综合应用路线三维实体造型、路线三维模型简化、计算机动画、虚拟现实等技术，采用 OPenGL三维图形库和 VC计等开发工具，实现了路线三维虚拟场景的实时动态显示，并与路线平、纵、横一体化设计相结合，使得三维可视化技术不仅用于设计成果的直观表达，而且融入整个设计过程中，从而实现本文提出的二维与三维相结合的设计思想。 6）结合铁道部和湖南省的有关科研课题，在导师的指导和其它同志的协助下，以本文所述的理论和算法为基础，主持或参加开发了多个铁路和公路路线CAD软件包，已在多家生产单位推广，成功地应用于多条铁路和公路路线的设计中。通过大量实践验证了理论和算法的正确性。更多还原

【Abstract】 This thesis applied synthetically those theories and technologies of computer graphics, computational geometry and geometrical modeling, scientific computation visualization, interactive, virtual reality, computer animation etc, to research thoroughly and carefully on several critical technology of computer aided alignment design, such as digital terrain model, interactive alignment, 3D modeling of route entity, simplification of 3D model, showing realistic image and dynamic and real time display of 3D route scene etc. By thoroughly analyzing the relation between the 2D horizontal, vertical and cross-section design and the 3D visual design, the conclusion could be reached that both are not substituted mutually (this being advocated and the other being cut down), but are mutually replenishing, and supplementing and complementing each other. They should be combined closely and applied synthetically. Based on this idea, the research work was carried out and closely centered on the theories and methods whose characteristic was combining 2D design with 3D design . Consequently not only the improvement of traditional methods of the 2D horizontal, vertical and cross section design but also the researches and applications of some new technologies such as 3D visualization , virtual reality etc, had been laid stress on in this thesis .The chief research contents and achievements could be summarized as follows:1) Based on the theories of Delaunay triangulation and constrained Delaunay triangulation, the algorithm for fast and integrally creating irregular triangulation net adapted to railway and highway alignment design was put forward and realized. It adopted an integral creating TIN technology which need not divide an enormous sum of topography points into some pieces in advance and could build a whole continuous strip triangle net without seams. Benefit from that, the question of bordering caused by dividing the points into pieces was avoided. The building speed achieved 40000 -45000 triangles per second on normal PII computer, furthermore, the influences of topography characteristic edges were concerned in computation course. The algorithm had such characteristics as the numberof points it once dealt with was limitless, with the whole TIN being continuous without seams, the building speed very high, the net shape top excellent , the precision very high and the use wide etc. It has been verified by its successful applications. Up to now, it has accomplished the design works of near 1000 kilometers highway and more than 2000 kilometers railway .2) In order to eliminate the defects drawn from the preceding route CAD systems into the horizontal design, the vertical design and the cross section design separated, in the thesis a new road design method had been presented for the first time that was to integrate the horizontal plan, the vertical profile map , the cross-section map and the 3D perspective map of the route on the same interface. It realized the alternate design and the interrelated design of the horizontal plan, the vertical profile map and the cross-section map and provided a great deal of information query functions which made the designer give adequate considerations to the other two aspects when being engaged in the one aspect of the three kinds of design. The CAD systems developed on these grounds not only retained the relative independence but also laid more stress on the interrelation among the horizontal design, the vertical design and the cross-section design, therefore were more in accordance with those characteristics of route design.3) The problem of 3D modeling of route entities was solved by the boundary expressing method based on the idea of dividing and conquer. This method divided the complicated route entities into several essential factor sub-entities. The 3D entity modeling method of each sub-entity was worked out respectively to accomplish each modeling, then assembled the various models. The theory of constrained Delaunay triangulation was applied to develop the algorithm of "更多还原