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几何模型化及其计算机实现
苏鸿根
Subtype工学硕士
Thesis Advisor陈由迪
1981-09-01
Degree Grantor中国科学院自动化研究所
Place of Conferral中国科学院自动化研究所
Degree Discipline计算机应用技术
Keyword计算机图形学 Interactive Uomputer Jraphics Uad System Geometric Modelling Ghepe Kepresentation Uonditions For well-Formed Surface Modlling Ge
Abstract三维计算机图形学是一门近年来迅速 发展的综合性学科,它的形成依赖于计算 机技术与数学方面的显著成就,而且可以 说几何模型化为之奠定了理论基础,从而 使之迈进入一个高级阶段。例如当我们研 制一个用作计算机辅助设计与制造机械零 件的系统时,首先迫切需待解决的问题是 :怎样合理有效地定义、构造、产生与管 理这些物体的可被设计算机识别的三维形状 描述,这就是属于几何模型探讨的内容 之一. 本文将讨论各种有效的模型化方法如 线性变换、参数化形状、形状运算与Euler 运算等,并提出一种实用的较简洁的数据 结构将它们统一起来.这种三维图形数据 表示包括几何与拓扑两个方法,它既能满 足数学上的合式条件,也具备形状运算中 所要求的自相容性.实验证明这种数据结 构的计算机实现是可行的. 文中还较详细介绍一个按上述原则研 制成的三维交互计算机图形显示系统,是 以产生机械制造工业所需求的大部分形状 ,即各种由平面与二次曲面构成的几何体 .该软件系统采用标准的FORTRAN语言编 写,运行在NOVA系列计算机的RDOS实时磁 盘操作系统上,输出为Tektronix4014型图 形显示器,具有一定的通用性.实用程序 中也提供许多参数价值的技巧或方法,如 引进有关类型标志信息值得相应的计算或 处理过程大的简化,采用面表构造法实现 一般公认难以满足的形状运算自相容要求;等. 最后附录一份完整的FORTRAN程序清单 文件,以及运行中打印的实际数据与现场 拍摄的部分图片,供分析参数.
Other AbstractGeometric modelling is an important topic of current research on three-dimensional computer graphics. It involves reasonably and efficiently entering, defining or constructing,, creating, and manipulating shape information which is a computer-understandable description for solid objects, Many model!ing techniques have been widely used in the design, analysis, and implementation of existing CAD systems. Geometric modelling will become centrally concerned with the unification of these diverse techniques via common representations of objects. This paper focusses on various efficient efficient modelling me- thods, e.g. linear transformations, parameterized shapes , shape operations, Euler operations and 2 1/2 D shapes, and proposes a flexible 3-D data representation to unify them.A graphic data structure may be formally defined as a pair(D,ρ),where D={d1,……,d} is a set of data elementa and ρ={R1, …,Rr} is a set of m-ary relations such that vi Ri,1≤i ≤r,m≥2,n,r,i,m ∈N0(i.e. the set of positive integers). Data elements are to determine the Geonetric position,and dimension of a solid in the Euclidean space, using coordinates of each point, direction cosines of lines or curves, or normal vectors of planes or equation parameters of its surface, Hery relations exhibit the solid coherence, including nine topologic properties auch as containment,naighborhood,selfcorrespondence, atc..The shape representation by seometry and topology ooth satisfies mathematically well-formed conditions and possesses self-consistency in graphics operations.And its computer implementation has been proven. Described in detail in the paper is an interactive 3-D compuler graphics display ayatem which has been developed based on the above guiding principle,capaole of generating images of most of shapes required in the mechanical mapufacturing industry,a.g.polyhedra ooundea by planes and quairic aurfaces.The aystem aolfware in PORTRAH runa under hte RDOS on a HOVA-3machine with 32XW(16 bit)as well as two 4.8B dlaks.The output is a Tektronlx 4014-1 diaplay terninal. Finally aome futre prospects or geometric modelling are briefly disoussed.
shelfnumXWLW34
Other Identifier34
Language中文
Document Type学位论文
Identifierhttp://ir.ia.ac.cn/handle/173211/7113
Collection毕业生_硕士学位论文
Recommended Citation
GB/T 7714
苏鸿根. 几何模型化及其计算机实现[D]. 中国科学院自动化研究所. 中国科学院自动化研究所,1981.
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