【作者】 江资斌；

【导师】 向南平；

【作者基本信息】 中南大学 ， 大地测量学与测量工程， 2003， 硕士

【摘要】 三维景观交互设计若干技术研究是基于地球多维信息可视化以及三维虚拟建设和工程设计的需要而提出来的。三维景观交互设计技术研究同当前研究的热点三维可视化技术、虚拟现实与视景仿真技术以及三维GIS技术有着密切的关系。本文从实际需求出发，就三维景观交互设计技术，研究了与其有关的三个方面的问题：三维景观可视化建模方法、三维交互技术实现关键算法和三维景观交互设计原型系统研究。 本文首先探讨了3DGIS数据模型的研究进展及存在的问题。接下来简述了地形景观中DEM的概念、形式及简化生成算法，实验构建了一个真实的地形景观模型。对于构筑物景观，剖析了建筑物景观的特征，阐述了建筑物由二维数据向三维数据扩展的方法以及复杂地物的独立建模解决方案，同时根据房屋建筑物的数据来源特点以及房屋建筑物的侧面、顶面特征剖析，通过定义一定的数据结构和利用纹理映射技术实验构建了具有真实感的三维房屋建筑物。在植物建模介绍中，对具有代表性的植物造型和绘制方法进行了评述，通过贴图法构建了比较真实的三维树木景观，其构建方法可以延伸到花卉、盆景等景观的建模。 高效的交互算法是三维景观交互设计系统必不可少的一部分，很大程度上决定着三维景观交互系统的功能和可用性。基于三维交互技术的难点所在，本文接下来介绍了构建三维景观交互设计系统所设计的三维交互关键算法，提出用四元组来表示旋转变换的状态，用鼠标跟踪球算法来实现用鼠标实现三维旋转变换，并研究实现了地形三维实时交互的两种显示。为了模拟现实生活中的光照，使计算机绘制的场景接近现实，结合OpenGL编程，非常形象地模拟了地理空间中的点光源、锥形光源、平行光源，并实现了对它们的交互控制。 最后，为了验证本文所提出的建模方法、真实感图形绘制技术和交互关键算法，作者运用面向对象的方法，在Windows环境下利用Visual C++6.0结合OpenGL编程，基于COM技术独立从底层开发研制了三维建模与交互工具Real3DM，同时利用此工具开发了三维景观交互设计系统VisualScene。通过实验有力地验证了作者所提出地建模方法和交互关键算法的合理性与可行性。更多还原

【Abstract】 Research on some Techniques of Interactive Designing of 3D Landscape,which put forward from the requirements of the visualization of the earth’s multi-information and the three-dimensional virtual construction or engineering design,has a close relationship with three of the most popular research points :the technique of 3D visualization,the technique of virtual reality or scene emulation and the technique of 3DGIS.In this dissertation,for the requirements of application,three related aspects about interactive design of 3D Landscape are studied,which are the visual modeling methods of 3D landscape,the key algorithms of the realization of 3D interaction technique and a prototype system--VisualScene.Firstly,the dissertation probes some problems of the current 3DGIS data models,then the author gives a brief introduction of the conception.the formation and simple production algorithms of DEM in terrain landscape and constructs a real terrain landscape by experiment.As for the constructions.the author dissects the feature of constructions and expounds how to model 3D constructions based on 2D data and the modeling method for complicated constructions.Based on the feature of house,such as data source ,obverse, profile etc. Using the data structure and texture mapping techniques in this thesis.a real 3D house can be erected.On plants modeling,an appraisal is made for the mostly used plants modeling and rendering methods.Trees can be modeled by mipmap method , moreover,this method can also be used to model flowers and potted landscapes.For the design of prototype system, efficient 3D interaction algorithms cann’t be omitted,because the system’s function and utility are determined by them at large extent.As for the difficulty of 3D interaction,the author designs his own 3D interaction algorithms.which using quaternion to stand for rotation status and mouse trackball algorithm to realize three-dimensional rotation.On the other hand.two kinds of realtime interactive rendering of terrain model are presented.By OpenGL programming.direct light.point light and spot light are visualized in shape to simulate the light of our environment.ln this way.a more real scene can be displayed in the computer ,furthermore,the light can be controlled by the user.Finally, in order to test and verify the modeling method,the rendering techniques of real graphic and the key algorithms of three-dimensional interaction ,a tool Real3DM for 3D modeling and interaction is developed using Visual C++6.0 &OpenGL and COM technology on the platform of Windows 2000.Using this tool,a prototype system for Interactive Designing of 3D Landscape named VisualScene is also developed.Experimental results show the reasonability and practicability of the modeling methods and the key algorithms for 3D interaction.更多还原