排序方式: 共有23条查询结果,搜索用时 15 毫秒
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介绍了小波分析理论在曲面去噪中的应用,在所设计的原始曲面上随机设置噪声,对含噪声的原始曲面型值点数据进行Hilbert扫描和小波分解,提取低频分量,再应用Unigraphics软件中的NURBS完成曲面重构,并对曲面重构的精度和效率进行了分析、验证。 相似文献
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These days consumers’ various demands are accelerating research on apparel manufacturing system including automatic measurement,
pattern generation, and clothing simulation. Accordingly, methods of reconstructing human body from point-clouds measured
using a three dimensional scanning device are required for apparel CAD system to support these functions. In particular, we
present in this study a human body reconstruction method focused on two issues, which are the decision of the number of control
point for each sectional curve with error bound and the local knot removal for reducing the unusual concentration of control
points. The approximation of sectional curves with error bounds as an approximation criterion leads all sectional curves to
their own particular shapes apart from the number of control points. In addition, the application of the local knot removal
to construction of human body sectional curves reduces the unusual concentration of control points effectively. The results
may be used to produce an apparel CAD system as an automatic pattern generation system and a clothing simulation system through
the low level control of NUBS or NURBS. 相似文献
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直线刀轨的NURBS变换 总被引:1,自引:0,他引:1
针对高速、高精度加工中NURBS刀轨生成的需求,提出了一种基于直线刀轨的NURBS刀轨生成算法.该算法根据相邻直线刀轨的几何特征,通过对直线刀轨分段的方法,从直线刀轨中识别出适合NURBS变换的轨迹段和不适合NURBS变换的轨迹段,并把适合NURBS变换的段变换成NURBS.如果拟合误差大于容许误差值,则在误差最大的数据点再次进行分段处理后重新变换成NURBS.算法应用实例表明,该算法具有可行性和实用性. 相似文献
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作物三维可视化将为作物生长动态预测、栽培管理调控、作物株型设计等提供形象逼真的可视化工具,从而有力促进虚拟农业和信息农业的发展。针对小麦形态结构复杂、叶片三维可视化不易表达的问题,基于田间实测数据和NURBS曲面建模实现了小麦叶片的三维重建。首先,通过田间实验定期观测小麦形态数据(叶长、叶宽、茎叶夹角、叶片弯曲度、茎秆直径等),建立小麦叶片主脉控制点构造算法,将小麦形态数据转换为主脉控制点坐标;其次,确定所有控制点坐标和节点矢量,构建小麦叶片和叶鞘NURBS曲面;最后,借助Open GL图形库可实现小麦不同生育期的模拟模型,并实现了小麦叶片的扭曲形变。结果表明该方法选取的小麦形态数据具有代表性,重建的小麦叶片模型逼真度较高,接近实测模型,易于实现小麦生长过程的动态模拟。 相似文献
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This article discusses the designing method of complex shapes with NURBS. The general design process of curve and surface is put forward in this paper,and the correspondent mathematical expressions and computational method are also presented. Because of the superior feature of NURBS, these methods are very suitable for constructing different kinds of shapes,and easy to use in engineering applications. Finally,the authors summarize various kinds of method of geometry design, based on NURBS. 相似文献
8.
石祥钟 《中国农村水利水电》2005,(3):106-108
论述了采用非均匀有理B样条(NURBS)方法,在离心泵弯曲扩散管设计过程中构造曲线和曲面;系统地论述了弯曲形扩散的内外轮廓线、过流断面和扩散管表面的并互式计算辅助过程;利用ANSYS软件的CFD功能进行扩散管内部流动计算分析,为改进其设计提供可靠的依据;该方法对改进离心泵弯曲形扩散管的设计方法和提高其设计质量具有重要的意义。 相似文献
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提出了一种改进的裁剪曲面 Delaunay三角化的方法。将仅适用于凸多边形域的 Delaunay三角化方法扩展到可应用于任意形状并可带有任意孔洞的形式 ,并给出了算法所用数据结构和详细的步骤 ,讨论了单连通域的构建方式。最后给出了应用该方法实现的一些例子 相似文献
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