OpenCasCade(九)拓扑运算

1.1 描述

n shape为基类；

n Vertex顶点：一种0维形状对应于几何中的点；

n edge边：一种形状对应一条曲线,并在每个末端通过一个顶点来约束；

n wire线框：一个通过顶点互连的边的序列；

n face面：部分（二维）平面或者（三维）表面，被一个闭合线框约束；

n shell壳(qiao)：线框边界线的边连接的面的集合；

n solid实体：与一个壳绑定的三维空间的一部分；

n Compound solid复合实体：实体的集合；

1.2 OCBRepBuilderAPI_MakeVertex

建立拓扑的Vertex。

例：

OCTopoDS_Vertex V3;

OCgp_Pnt P = new OCgp_Pnt(-12, 8, -4);

OCBRepBuilderAPI_MakeVertex MV = new OCBRepBuilderAPI_MakeVertex(P);

V3 = MV.Vertex();

1.3 OCBRepBuilderAPI_MakeEdge

建立拓扑的Edge。

例1：两个几何点生成边

OCTopoDS_Edge BlueEdge, YellowEdge, WhiteEdge, RedEdge, GreenEdge;

BlueEdge = new OCBRepBuilderAPI_MakeEdge(

new OCgp_Pnt(-80, -50, -20), new OCgp_Pnt(-30, -60, -60)).Edge();

例2：两个拓扑Vertex生成边

OCTopoDS_Edge YellowEdge

OCTopoDS_Vertex V1, V2

V1 = new OCBRepBuilderAPI_MakeVertex(new OCgp_Pnt(-20, 10, -30)).Vertex();

V2 = new OCBRepBuilderAPI_MakeVertex(new OCgp_Pnt(10, 7, -25)).Vertex();

YellowEdge = new OCBRepBuilderAPI_MakeEdge(V1, V2).Edge();

例3：用几何直线生成边

OCgp_Lin line;

line= new OCgp_Lin(new OCgp_Ax1(new OCgp_Pnt(10, 10, 10),

new OCgp_Dir(1, 0, 0)));

OCTopoDS_Edge WhiteEdge = new OCBRepBuilderAPI_MakeEdge(line, -20, 10).Edge();

例4：用椭圆弧生成边

OCTopoDS_Edge RedEdge；

OCgp_Elips Elips =

new OCgp_Elips(new OCgp_Ax2(new OCgp_Pnt(10, 0, 0), new OCgp_Dir(1, 1, 1)), 60, 30);

RedEdge = new OCBRepBuilderAPI_MakeEdge(Elips, 0, System.Math.PI / 2).Edge();

例5：贝赛尔曲线生成边

OCGeom_BezierCurve curve = new OCGeom_BezierCurve(array);

OCBRepBuilderAPI_MakeEdge MEdge = new OCBRepBuilderAPI_MakeEdge(curve);

OCTopoDS_Edge GreenEdge = MEdge.Edge();

1.4 OCBRepBuilderAPI_MakeWire

建立拓扑的线框Wire。

例1：一条边生成线框

OCTopoDS_Edge Edge1;

OCTopoDS_Wire RedWire = new OCBRepBuilderAPI_MakeWire(Edge1).Wire();

例2：二两边生成线框

OCTopoDS_Edge ExistingWire;

OCTopoDS_Edge Edge3;

OCBRepBuilderAPI_MakeWire MW1 =

new OCBRepBuilderAPI_MakeWire(ExistingWire, Edge3);

if (MW1.IsDone())//是否可以生成线框

{

OCTopoDS_Wire YellowWire = MW1.Wire();

}

例3：线框与若干边组成线框

OCTopoDS_Wire ExistingWire2；

OCTopoDS_Edge Edge5，Edge6，Edge7；

OCBRepBuilderAPI_MakeWire MW = new OCBRepBuilderAPI_MakeWire();

MW.Add(ExistingWire2);

MW.Add(Edge5);

MW.Add(Edge6);

MW.Add(Edge7);

if (MW.IsDone())

{

OCTopoDS_Wire WhiteWire = MW.Wire();

}

1.5 OCBRepBuilderAPI_MakeFace

创建拓扑面；

例1：几何球面生成拓扑面

OCgp_Sphere sphere;

OCTopoDS_Face WhiteFace =

new OCBRepBuilderAPI_MakeFace(sphere, 0.1, 0.7, 0.2, 0.9).Face();

例2：Bspline曲面生成拓扑面

OCGeom_BSplineSurface curve ；

OCTopoDS_Face RedFace = new OCBRepBuilderAPI_MakeFace(curve).Face();

例3：闭合的线框形面拓扑面

OCTopoDS_Wire YellowWire = MW1.Wire();

OCTopoDS_Face BrownFace = new OCBRepBuilderAPI_MakeFace(YellowWire, false).Face();

1.6 OCBRepBuilderAPI_MakeShell

创建拓扑壳；

例1：BSpline曲面生成Shell

OCGeom_BSplineSurface BSpline;

OCTopoDS_Shell aShell = new OCBRepBuilderAPI_MakeShell(BSpline, false).Shell();

1.7 OCBRep_Builder

1.8 OCBRepBuilderAPI_Sewing

拓扑对象的缝合；

可以通过调节该类的第一个参数，来调整缝合连接部的精度；

例1：

OCTopoDS_Face FirstShape；

OCTopoDS_Face SecondShape；

OCBRepBuilderAPI_Sewing aMethod =

new OCBRepBuilderAPI_Sewing(0.000001, true, true, true, false);

aMethod.Add(FirstShape);

aMethod.Add(SecondShape);

aMethod.Perform();

OCTopoDS_Shape sewedShape = aMethod.SewedShape();

例2：闭合的SHELL缝合成SOLID

OCBRepBuilderAPI_Sewing sew = new OCBRepBuilderAPI_Sewing(0.01, true, true, true, false);

sew.Add(shell);

sew.Perform();

OCTopoDS_Shape shape = sew.SewedShape();

shape.Reverse();

solid = new OCTopoDS_Solid();

builder.MakeSolid(solid);

builder.Add(solid, shape);

1.9 OCBRep_Tool

实用的拓扑工具类—静态类；

(1) 拓扑边到几何线的转换；

public static OCGeom_Curve Curve(OCTopoDS_Edge E, ref double First, ref double Last);

(2) 拓扑面转换为几何面

public static OCGeom_Surface Surface(OCTopoDS_Face F);

public static OCGeom_Surface Surface(OCTopoDS_Face F, OCTopLoc_Location L);

1.10 OCBRepExtrema_DistShapeShape

拓扑极值运算。

可用于拓扑求交等。

例：曲线被曲线拆分

1.11 基本几何体拓扑对象

(1) 以下是基本几何的拓扑生成方式，包括立方体，椎体，柱体，球体等

n OCBRepPrimAPI_MakeBox

n OCBRepPrimAPI_MakeCylinder

n OCBRepPrimAPI_MakeCone

n OCBRepPrimAPI_MakeSphere

n OCBRepPrimAPI_MakeTorus

n OCBRepPrimAPI_MakeWedge

(2) 实例

例1：生成一个立方体并显示在VIEW中

OCAIS_InteractiveContext context；

OCTopoDS_Shape B1 = new OCBRepPrimAPI_MakeBox(200.0, 150.0, 100.0).Shape();

OCAIS_Shape aBox1 = new OCAIS_Shape(B1);

context.SetMaterial(aBox1, OCGraphic3d_NameOfMaterial.Graphic3d_NOM_PLASTIC, false);

context.SetColor(aBox1, OCQuantity_NameOfColor.Quantity_NOC_GREEN, false);

context.Display(aBox1, true);

转：https://www.cnblogs.com/amtf/articles/2285756.html

OpenCasCade(九)拓扑运算

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