三维地形生成及实时显示技术研究进展

三维地形是虚拟自然环境中不可缺少的因素，也是虚拟仿真领域中视景诉重要组成部分，该文将地形生成技术概括为基于真实地形数据的地形生成技术、基于分形技术的地仿真技术、基于数据拟合的地形信息技术等三大类，并分别介绍了这三类方法的相关理论和生成技术，还分析了各自的发展趋势，其中在基于真实数据的地形生成方面，按照离散ＬＯＤ模型、连续ＬＯＤ模型、多分辨率模型的发展顺序，重点介绍了地形实时显示技术中数据简化方面的

The Research Development of 3D Terrain Generation and Real-Time Display Techniques

Three dimensional terrain is one of important factors of the natural scenes in virtual environment. It is also a significant composition of view system in virtual simulation field. The paper presents terrain generation techniques based on real terrain datasets, and terrain simulation techniques that are based on fractal geometry as well as data fitting methods respectively. Among the terrain generation techniques based on real terrain datasets, emphasis is laid on the real time display of terrain and some typical data simplification algorithms are introduced according to their appearing time: discrete LOD, continuous LOD, and multiresolution model. Related conceptions and features of those algorithms are also discussed. In terrain simulation techniques based on fractal geometry, the paper gives an overview of several fractal modeling methods, and then makes a further discussion on two kinds of typical recursive subdivision plans of midpoint displacement that is the most practical approach in some applications. In data fitting techniques, plane fitting, curved surface fitting, and real terrain simulation according to some given topographic parameters are introduced. Finally, the development tendencies of all these techniques are discussed.