WHERE CorrespondingWeightsDataLists : (SIZEOF(WeightsData) = SIZEOF(SELF\IfcBSplineSurface.ControlPointsList)) AND (SIZEOF(WeightsData[1]) = SIZEOF(SELF\IfcBSplineSurface.ControlPointsList[1])); WeightValuesGreaterZero : IfcSurfaceWeightsPositive(SELF); END_ENTITY;...
CorrespondingWeightsDataLists : (SIZEOF(WeightsData) = SIZEOF(SELF\IfcBSplineSurface.ControlPointsList)) AND (SIZEOF(WeightsData[1]) = SIZEOF(SELF\IfcBSplineSurface.ControlPointsList[1])); WeightValuesGreaterZero : IfcSurfaceWeightsPositive(SELF); END_ENTITY; 1. 2. 3. 4. 5. 6. 7. 8....
6)重复度:B样条最常用的方式是Clamp BSpline,也就是对于p次B样条,起始参数和终止参数的重复度为p+1,能够使得B样条曲线的起点和第一个控制点P0重合,末点和最后一个控制点Pn重合。 举例:二阶B样条起始参数重复度为3,即 u_0 = u_1 = u_2 ,于是,在 u_2 处,有: N_0^2 = 1, N_1^2 = 0, N...
EXPRESS Specification ENTITY IfcBSplineCurveWithKnots SUPERTYPE OF(IfcRationalBSplineCurveWithKnots) SUBTYPE OF (IfcBSplineCurve); KnotMultiplicities : LIST [2:?] OF IfcInteger; Knots : LIST [2:?] OF IfcParameterValue; KnotSpec : IfcKnotType; DERIVE UpperIndexOnKnots : IfcInteger := SIZEOF(...
Surface fittingA heuristic criterion is proposed for optimizing knots in the B-spline surface fitting problem.The iterative surface fitting framework can well preserve geometric features.Our method is more efficient and yields more accurate results than DOM-based method....
t 4 0.5 t 5 0.75 Initializing live version Open Notebook in Cloud Contributed by:Yu-Sung Chang(2007) Open content licensed underCC BY-NC-SA Snapshots Details External Links Permanent Citation Cite this as Yu-Sung Chang(2007), "B-Spline Curve with Knots" Wolfram Demonstrations Project. demonst...
void _CSFDB_SetPGeom_BSplineSurfaceweights (const Handle< PColStd_HArray2OfReal > &p) Handle< PColStd_HArray1OfReal > _CSFDB_GetPGeom_BSplineSurfaceuKnots () const void _CSFDB_SetPGeom_BSplineSurfaceuKnots (const Handle< PColStd_HArray1OfReal > &p) Handle< PColStd_HArray1OfRe...
2. Semi-structured B-spline surfaces It is well known that the control points of a B-spline surface can be arranged as a grid. Each row of the grid has the same number of control points; so does each column. Therefore, the classical B-spline surface is a patch-based spline with struc...
B-spline B样条 (1978, De Boor C) 是样条曲线的一种特殊表达形式,是B-样条基函数的线性组合,是贝塞尔曲线的一般化。 B样条基函数 两个重要参数:节点 (knots) 和次数 (degress) 定义域被节点细分,分成很多个结节区间 每个基函数局部非零 基函数的次数可以人为给定 假设B-样条的基函数的定义域为[u0,um]...
B-spline surface B yangtiao qumianB样条曲面(Bsp一ine surface)用分段B样条多项式函数及控制点网格定义的面。基于B样条曲线,可以得到B样条曲面的表示式。给定(m+1)(n十l)个空间点列凡(i=0,1,…,m,]=0,1,…,n),则s(二,w)一艺艺尸。从,*(。)凡,,(w),该二0少=O u,功任[0,1」定义了kXz...