【作者】 张倩倩；

【导师】 淮永建；

【作者基本信息】 北京林业大学 ， 计算机应用技术， 2008， 硕士

【摘要】 随着虚拟现实技术、网络技术、计算机图形学等学科技术的迅猛发展,单机运行的三维可视化系统已经不再满足人们的需求,基于网络的三维可视化系统已经成为虚拟现实和虚拟景观中一个新的研究热点。论文提出的基于WEB的三维林木场景可以实现三维林木场景网络漫游和林业资源的网络共享,用户可以在WEB环境下浏览虚拟林业景观实现全方位多角度林业资源信息的交互。论文对目前三维地形、虚拟植物的建模和绘制方法进行了对比分析研究,重点讨论了森林植被景观中基于DEM数字高程模型的三维地形的建模和绘制方法、三维地形LOD的实时优化以及WEB环境下林木的三维建模和渲染方法,并对不同方法的优缺点进行了对比分析。针对网络环境下林木场景的特点提出了一种基于Java3D平台的林木场景实时建模和渲染方法。论文主要工作包括:研究了基于WEB的三维地形建模和纹理映射方法,提出了基于Java3D的三维地形LOD实时绘制方法;针对林木建模提出了基于Java3D的3DS数据文件解析方法,实现了Java3D场景图中树木三维建模;在虚拟树木的绘制方式上实现了基于几何和图像混合树木绘制方法,最终达到良好的视觉效果。为了实现WEB环境下林木场景的交互,讨论了Java3D平台下三维林木场景碰撞检测处理方法。更多还原

【Abstract】 With the development of Virtual Reality technology, networking technology and computer graphics etc, 3D virtrualization system running on a single machine no longer meets people’s need. WEB-based 3D virtualization system has been the research focus in the area of virtual reality and virtual landscape. WEB-based 3D Forest scene proposed in the paper achieves network roaming and forest resource data sharing. People can navigate and observe the scene in omni directions and multiple views.Comparative and analytic research on current technology of modeling and rendering of 3D terrain and virtual plants is made in the paper. The DEM terrain modeling and its real-time rendering, terrain rendering using LOD optimization, and the modeling and rendering of WEB-based virtual trees are the major topics of our discussion. After comparative analysis of advantages and disadvantages of different methods, a method to construct WEB-based forest scene and real-time rendering based on Java3D is proposed in this paper according to the characteristics of the forest scene.The main research work in this paper including methods to construct WEB-based 3D terrain model and texture mapping, LOD real-time rendering technology based on Java3D. Against the problem of tree modeling, the algorithm based on Java3D to analysis 3DS format file is completed to model virtual trees on Java3D scene graph. The mixed rendering method of geometry rendering and image-based rendering is applied to make forest scene better visual effects. Furthermore, topics on collision detection are discussed based on Java3D technology to achieve interaction in WEB-based forest scene.更多还原