Patran基础教程03-几何建模

S3-1PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation第3部分几何建模S3-2PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation基本概念S3-3PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●Patran结合拓扑结构来定义几何●Patran中的拓扑实体是●角点保留了边,面,体的位置●在Patran语法中，所有的拓扑元素都是可以被光标选取的(例如Surface10.2)拓扑结构VertexEdgeFaceBodyS3-4PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation案例学习:简单实体的拓扑●创建一个1x1x1蓝色参数化实体●点击GeometryApplications按钮.●把Action/Object/Method设成Create/Solid/XYZ.●Apply.●打开实体标签S3-5PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●模型显示如下Solid1分解图看拓扑关系的定义案例学习:简单实体的拓扑S3-6PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●显示点和体的标号●显示标号按下面图示案例学习:简单实体的拓扑S3-7PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporationSolid1.2Solid1.2Solid1.4Solid1.6●首先,看看体的面是如何拓扑标识的案例学习:简单实体的拓扑S3-8PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●然后,看体的边例如Solid1.2.3案例学习:简单实体的拓扑S3-9PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●先删掉Point7,再在体的顶点上创建一个点.●在Geometry中,把Action设为Delete.●把Object设为Any.●在SelectMenu中选择Point.●在GeometricEntityList中选择Point7.●Apply.案例学习:简单实体的拓扑S3-10PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●在Point7所在的位置创建一个点.●把Action/Object/Method设为Create/Point/XYZ.●在PointCoordinatesList输入顶点Solid1.2.3.2.●Apply.案例学习:简单实体的拓扑S3-11PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●由参数化实体创建参数化面,例如一个面的位置u=0.5●SetAction/Object/MethodtoCreate/Surface/Extract.●SettheuParametricValueto0.5.●SelectSolid1forSolidList.●Apply.●将设置改为v=0.5，w=0.5，重复操作.案例学习:简单实体的拓扑S3-12PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●现在通过擦除实体来观察体中的参数化面.●Display/Plot/Erase.●EnterSolid1forSelectedEntities.●Erase.案例学习:简单实体的拓扑S3-13PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation●将这三个面阴影显示.●Clickonthefollowingicon.●面相交处的点的參数坐标是什么?●Ans:(0.5,0.5,0.5)案例学习:简单实体的拓扑S3-14PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation几何拓扑●和不同几何类型相关的拓扑:PointList0DCurveList1DSurfaceList2DSolidList3DPointPoint10CurveCurve20.1(Vertex)Curve20SurfaceSurface30.2.1(Vertex)Surface30.2(Edge)Surface30SolidSolid40.3.2.1(Vertex)Solid40.3.2(Edge)Solid40.3(Face)Solid40S3-15PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation几何创建Point(蓝绿色)点是零维的空间CAD元素.它代表了一个空间位置.当创建线,面,体时,Patran会自动创建点点会在顶点创建,例如面的顶点(“corners”)没必要总是由点来构建实体,例如由点到面XYZ9YZXS3-16PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation几何创建(续)一条线是单个参数变量ξ1的矢量函数;它可以有多种数学表达形式:Curve(黄)(X,Y,Z)=function(ξ1)一条线有:两个点,每端一个一个参数坐标(ξ1),其范围从0.0(P1位置,起始点)到1.0(P2位置)用bar单元划分网格ξ1P2ξ1P1P(ξ1)ZYXZXY55BarElementS3-17PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation几何创建(续)面的类型可以是简单(绿)或复杂/一般(紫红)一个简单的面可以表达成两个参数变量ξ1,ξ2矢量函数:Surface(简单或复杂)(X,Y,Z)=function(ξ1,ξ2)一个简单的面有:3或4个边参数坐标原点，坐标范围从0到1一个由3边组成的简单面,第四条边已经退化12P2P1P4P3ξ2ξ1ξ2ξ1ZYXZXYP(ξ1,ξ2)S3-18PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation几何创建(续)简单面一个简单的面可以用IsoMesh(mapped)或Paver(free)网格生成器来划分网格在面上显示线Surface1IsoMeshMeshofSurface1线上节点的参数值不变ξ1ξ21/31/32/32/3线的参数值不变CurvesFromSurface1S3-19PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation几何创建(续)复杂的面●一个复杂的或经过修剪的面(紫红色),其特征是有多于4个的边,并且可以有内部的边●不能参数化定义,例如不能使用参变量ξ1,ξ2●经过“修剪”后的参数化面●必须用Paver网格生成器划分网格●首先划分面的周边GeneralTrimmedSurface(8edges)PaverMeshofSurface面的周边S3-20PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporationYZX几何创建(续)体(简单或复杂)●简单或參数化实体(蓝色)●三个参变量的矢量函数表达ξ1,ξ2,ξ3●一个简单的实体包含:●4到6个边界面●参数原点和坐标，其范围从0到1●一个简单的体有4到5个面组成的话，其余的面就已经退化了●参数化体用IsoMesh(mapped)网格生成器来生成六面体,楔形体,或四面体网格ξ1ξ2ξ3P8P7P6P4P3P2P1P5P(ξ1,ξ2,ξ3)S3-21PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporationTetrahedralMeshB-RepSolid几何创建(续)复杂体●复杂或非参数化体(N个面)(白色)●非参数化实体可以是Patran本身的B-Rep(边界表征)或parasolidB-Rep●CAD体可以被转化成Patran本身的B-Rep或parasolidB-Rep体,然后用自动的TetMesh算法生成网格●先用三角形划分面,然后用四面体划分体●类似Paver网格生成器S3-22PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporationPlaneVector几何创建(续)平面,向量●平面和矢量被用作特定的几何操作,例如体被平面切割●一个平面可由表示其法向和面内的点的矢量唯一确定●Patran矢量由大小,方向和原点来定义S3-23PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation几何的导入导出S3-24PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation文件导入选项S3-25PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation文件输导选项(续)几何内核类型CAD零件标准格式S3-26PAT301,Section3,September2010Copyright2010MSC.SoftwareCorporation导入CATIACAD模型可以导入几种CATIA文件CATIAV4Model:modelfile,e.g.dogbone.modelCATIAV5CATPart:partfile,e.g.catbone.CATPartCATIAV5CATProduct:productfile,e.g.crockbone.CATProductCATXPRESFile:outputfile,e.g.otherbone.catS3-27PAT301,Section3,September2008Copyright2008MSC.SoftwareCorporationCATIACAD模型导入●CATIAV4Model,CATIA选项…包括●转成Parasolid格式:Yes●导入的几何将是Parasolid类型的几何●体类型●Selectsimple(6faces)orB-repsolid●TrimmedSurfaceType●选择简单(4个边)或一般裁剪面●ImportNoShowEntities:Yes●CATIAV4entitiesclassifiedasNoShowwillbeimported●ImportAttributes●选Yes,和几何相关的属性将被导入；选No,导入较快。●EntityLayers●选择导入所有的层，或指定的层●CreateGroupsfromLayers●根据CAD层自动创建Patran组y●Groupname:prefix_LnCATIAV4ModelS3-28PAT301,Section3