GFFD:Generalized free-form deformation with scalar fields

INTRODUCTIONNURBSandpolygonalmeshesaretwomajorrepresentationschemesformodelingcomplex 3Dobjects.Althoughsomeeffectiveshapeeditingtoolsarenowavailableforbothofthem ,modify ingtheshapeofanobjectintuitivelyisstillte diouswork .Thisisparticularlytrueforsomesp…     

CAGD在工程设计中的应用

计算机辅助设计（CAD）,不仅可以替代绘图的手工作业,充当新的绘图工具,更是一种辅助设计手段。主动地应用和开发CAD技术的辅助设计功能,将有助于提高工程设计的效率和质量。本文通过若干实例,初步探讨了CAD技术的分支CAGD的概念及应用方向,提出了一些应用CAGD手段解决工程实践问题的方法。     

车身外形曲面CAGD系统的开发与应用

在分析车身外形曲面设计规律的基础上，从ＮＵＲＢＳ方法的原始定义出发推导了 具有实用意义的算法，并建立了用于车身外形曲面几何造型的ＣＡＧＤ系统，最后给出了 设计实例．     

实现3个二次曲面GC^1拼接的一种具体算法

研究拼接3个二次代数曲面所形成的混合代数曲面的整体参数化问题,提出相应的参数化方法,给出了具体算法．利用拼接曲面在仿射坐标系下的简单表达式,不分块直接对混合拼接曲面进行参数化．     

CAGD课程建设与教学改革研究及实践

本文介绍了CAGD课程建设及教学改革的探索与研究。包括课程建设与教学改革的思路和目标、教材建设、教学方法的改进、教学实习的设计及取得的主要成果。     

AutoCAD教学与创新能力培养

文中阐述了AutoCAD教学中存在的问题,提出以设计思想带动教学、以管理思想推动教学、将创新设计引入考试、用更高水平要求教师的教改思路,试图将共性学习与个性学习相结合,着力培养学生的创新能力.     

基于Mastercam和CAGD图解法求斜切椭圆筒钣金展开图的应用

以椭圆筒为例,针对钣金结构件展开计算问题,提出了基于Mastercam图形软件的CAGD图解法,使传统的展开放样工作变得简单和高效,所得到的展开图精准且不需要额外加工。该图解法具有较强通用性与实用价值,可在工程应用中进行推广。     

Convexity-preserving interpolation of trigonometric polynomial curves with a shape parameter

In computer aided geometric design(CAGD) ,it is often needed to produce a convexity-preserving interpolating curve according to the given planar data points. However,most existing pertinent methods cannot generate convexity-preserving in-terpolating transcendental curves;even constructing convexity-preserving interpolating polynomial curves,it is required to solve a system of equations or recur to a complicated iterative process. The method developed in this paper overcomes the above draw-backs. The basic idea is:first to construct a kind of trigonometric polynomial curves with a shape parameter,and interpolating trigonometric polynomial parametric curves with C2(or G1) continuity can be automatically generated without having to solve any system of equations or do any iterative computation. Then,the convexity of the constructed curves can be guaranteed by the appropriate value of the shape parameter. Performing the method is easy and fast,and the curvature distribution of the resulting interpolating curves is always well-proportioned. Several numerical examples are shown to substantiate that our algorithm is not only correct but also usable.     

GFFD: Generalized free-form deformation with scalar fields

The novel free-form deformation(FFD) technique presented in the paper uses scalar fields defined by skeletons with arbitrary topology. The technique embeds objects into the scalar field by assigning a field value to each point of the objects. When the space of the skeleton is changed, the distribution of the scalar field changes accordingly, which implicitly defines a deformation of the space. The generality of skeletons assures that the technique can freely define deformable regions to produce a broader range of shape deformations.     

实现3个二次曲面GC1拼接的一种具体算法

研究拼接3个二次代数曲面所形成的混合代数曲面的整体参数化问题,提出相应的参数化方法,给出了具体算法.利用拼接曲面在仿射坐标系下的简单表达式,不分块直接对混合拼接曲面进行参数化.