简介:Inthispaper,theproblemoffindingtheintersectionofatriangularBezierpatchandaplaneisstudied.Forthedegreethatonefrequentlyencountersinpractice,i.e.n=2,3,anefficientandreliablealgorithmisobtained,andcomputationalstepsarepresented.
简介:RationalBéziersurfaceisawidelyusedsurfacefittingtoolinCAD.WhenalltheweightsofarationalBéziersurfacegotoinfinityintheformofpowerfunction,thelimitofsurfaceistheregularcontrolsurfaceinducedbysomeliftingfunction,whichiscalledtoricdegenerationsofrationalBéziersurfaces.Inthispaper,westudyonthedegenerationsoftherationalBéziersurfacewithweightsintheexponentialfunctionandindicatethedifferenceofourresultandtheworkofGarc′?a-Puenteetal.Throughthetransformationofweightsintheformofexponentialfunctionandpowerfunction,theregularcontrolsurfaceofrationalBéziersurfacewithweightsintheexponentialfunctionisdefined,whichisjustthelimitofthesurface.Comparedwiththepowerfunction,theexponentialfunctionapproachesinfinityfaster,whichleadstosurfacewiththeweightsintheformofexponentialfunctiondegeneratesfaster.
简介:Inthispaper,wepresenttwonewunifiedmathematicsmodelsofconicsandpolynomialcurves,calledalgebraichyperbolictrigonometric(AHT)Béziercurvesandnon-uniformalgebraichyperbolictrigonometric(NUAHT)B-splinecurvesofordern,whicharegeneratedoverthespacespan{sint,cost,sinht,cosht,1,t,...,t~(n-5)},n≥5.ThetwokindsofcurvessharemostofthepropertiesasthoseoftheBéziercurvesandB-splinecurvesinpolynomialspace.Inparticular,theycanrepresentexactlysomeremarkabletranscendentalcurvessuchasthehelix,thecycloidandthecatenary.Thesubdivisionformulaeofthesenewkindsofcurvesarealsogiven.Thegenerationsofthetensorproductsurfacesarestraightforward.Usingthenewmathematicsmodels,wepresentthecontrolmeshrepresentationsoftwoclassesofminimalsurfaces.
简介:传统的建模方法不能精确表示曲面体的弯曲度,针对这些不足,本文采用有理Bezier方法构建曲面模型,给出了椭球体标准型有理二次Bezier控制点和权因子的求解算法;利用非有理Bezier的升阶算法将有理二次Bezier升阶为有理三次Bezier,给出了标准型有理三次Bezier曲线控制点和权因子的求解算法,构建了有理双三次Bezier椭球体曲面模型,通过调整控制点或权因子参数可生成如葫芦、青椒、鸡蛋等光滑的曲面模型.实验表明,该算法具有很好的设计灵活性和交互性,为构建曲面模型提供了新的技术支持.
简介:
简介:THEAPPLICATIONOFG ̄1JOINOFRECTANGULARANDTRIANGULARBEZIERPATCHESINSURFACEMODELINGWangTianjun;TangRongxiSMOOTHSURFACEINTERPOLATI...
简介:Weestablishseveralfundamentalidentities,includingrecurrencerelations,degreeelevationformulas,partitionofunityandMarsdenidentity,forquantumBernsteinbasesandquantumBeziercurves.WealsodeveloptwotermrecurrencerelationsforquantumBernsteinbasesandrecursiveevaluationalgorithmsforquantumBeziercurves.Ourproofsusestandardmathematicalinductionandotherelementarytechniques.
简介:对[0,1]上的L—可积函数ф及α>0定义下列B—D—B算子;本文研究了Mna(ф,x)当α>0时,在LP(0,1](1≤p<+∞)的一致逼近;当α≥1时在LP[O,1]及L1P[0,1]逼近度的量化估计。作者在文[4]中定义了B—D—B算子:其中fnk(X)称为Bézeief基函数文[4]研究的是B—D—B称子在C[0,1]空间中的逼近性质,本文继续[4]的工作,专研究这个算子在LP[0,1](1≤P<+∞)的逼近性质,证明了Mna(фX)当α>0时在LP[0,1]中为一致逼近,并得到了当α≥1时在LP[0,1]及L1P[0,1]中逼近度的量化估计。
简介:研究了作大范围旋转运动高度和宽度均沿着梁长度方向变化的锥形悬臂梁动力学问题.采用Bezier插值方法对柔性梁的变形场进行描述,考虑柔性梁的纵向拉伸变形和横向弯曲变形,计人由于横向弯曲变形引起的纵向缩短,即非线性耦合项.运用第二类拉格朗日方程推导出作旋转运动锥形梁的动力学方程,并编制了动力学仿真软件,对作旋转运动锥形梁的频率和动力学响应进行研究.结果表明:不同锥形梁截面的动力学响应和系统频率将有明显差异,因此对实际系统合理建模,将能得到更为精确的结果.