【摘要】 体绘制技术是目前科学计算可视化研究的一个重要组成部分,对地质体内部属性分布的可视化有重要意义。该文针对地学研究中几何建模和属性建模同样重要的特点,基于一种矢栅一体化的混合数据模型,对地质体表面采用三角面片描述几何形状,对地质体内部采用基于八叉树的自适应网格剖分技术描述内部属性特征。对网格剖分后的体数据,采用体元投射的体绘制技术进行地质体内部属性可视化,显示出很好的效果,具有实际应用意义。更多还原

【Abstract】 The research of 3D GIS includes some basic and important issues,such as data creating and preparing,data model,data organization,data visualization and three dimensional space analyses.Among them,the visualization for 3D GIS is a hot research area.The scientific computing visualization has been broadly used in the field of geology and the technique of volume rendering is an important component of current scientific computing visualization research.This new technique can help people understand the inner attribute distribution of the underground geological objects by the means of visualization.So this article adopts a new hybrid data model that integrates both the vector and raster model,and takes the advantage of volume rendering technique to do the research of 3D GIS visualization.The hybrid data model takes consideration of the characteristics of geometry modeling and attribute modeling in geology.In the implementation,the triangular faces are used to model the geometry and the octree-based adaptive meshing refinement technique is used to model the inner attribute of the geological objects.For the meshing data,the authors analyze the most frequently used volume rendering algorithms and adopt the algorithm named cell projection to visualize the inner attribute.The result shows considerably good imaging and high efficiency.In the performance test,a single geological object is decomposed at the resolution of 32*32*32 and 128*128*128 respectively,which accordingly cost 0.048375 and 1.058399 seconds.The result shows great practical application value.更多还原