OpenCasCade(八) 拓扑几何
1.1.1 拓扑几何描述
1.1.2
OCBRepPrimAPI_MakePrim
(1) 功能说明：swept(拉伸)
(2) 构造函数
OCBRepPrimAPI_MakePrism(OCTopoDS_Shape S, OCgp_Vec V, bool Copy, bool Canonize);
OCBRepPrimAPI_MakePrism(OCTopoDS_Shape S, OCgp_Dir D, bool Inf, bool Copy, bool Canonize);
(3) 参数说明
OCTopoDS_Shape：扫掠拓扑对象
OCgp_Vec：扫掠的方向及大小（向量）
OCgp_Dir：扫掠的方向及大小（单位向量）
Copy：默认值为FALSE; 若为TRUE，则得用扫掠对象副本进行扫掠
Canonize：默认值为TRUE;
Inf:默认值为TRUE; if Inf is false the prism is semi-infinite (in the direction D).
(4) 实例
例1：拓扑点扫掠成边
OCTopoDS_Vertex V1 =
new OCBRepBuilderAPI_MakeVertex(new OCgp_Pnt(-200, -200, 0)).Vertex();
OCTopoDS_Shape S1 =
new OCBRepPrimAPI_MakePrism(V1, new OCgp_Vec(0, 0, 100), false, false).Shape();
例2：拓扑边扫掠成面
OCTopoDS_Edge E =
new OCBRepBuilderAPI_MakeEdge(new OCgp_Pnt(-150, -150, 0),
new OCgp_Pnt(-50, -50, 0)).Edge();
OCTopoDS_Shape S2 =
new OCBRepPrimAPI_MakePrism(E, new OCgp_Vec(0, 0, 100), false, false).Shape();
例3：拓扑边框扫掠成体
OCTopoDS_Edge E1，E2，E3；
OCTopoDS_Wire W = new OCBRepBuilderAPI_MakeWire(E1, E2, E3).Wire();
OCTopoDS_Shape S3 =
new OCBRepPrimAPI_MakePrism(W, new OCgp_Vec(0, 0, 100), false, false).Shape();
1.1.3 OCBRepPrimAPI_MakeRevol
(1) 功能说明：旋转面
(2) 构造函数
public OCBRepPrimAPI_MakeRevol(OCTopoDS_Shape S, OCgp_Ax1 A, bool Copy);
public OCBRepPrimAPI_MakeRevol(OCTopoDS_Shape S, OCgp_Ax1 A, double D, bool Copy);
(3) 参数说明
OCTopoDS_Shape：要进行旋转的拓扑对象
OCgp_Ax1：用某一坐标方向的直线作为旋转轴
Copy：是否用要旋转对象的副本来进行操作，默认值为FALSE;
D：旋转的角度；
(4) 实例
例1：拓扑点形成圆弧
OCTopoDS_Vertex V1;
OCgp_Ax1 axe = new OCgp_Ax1(new OCgp_Pnt(-170, -170, 0), new OCgp_Dir(0, 0, 1));
OCGeom_Axis1Placement Gax1 = new OCGeom_Axis1Placement(axe);
OCAIS_Axis ax1 = new OCAIS_Axis(Gax1);
OCTopoDS_Shape S1 = new OCBRepPrimAPI_MakeRevol(V1, axe, false).Shape();
例2：拓扑边形成柱面
OCTopoDS_Edge E;
OCAIS_Shape ais3 = new OCAIS_Shape(E);
OCgp_Ax1 axe = new OCgp_Ax1(new OCgp_Pnt(-100, -100, 0), new OCgp_Dir(0, 0, 1));
OCGeom_Axis1Placement Gax2 = new OCGeom_Axis1Placement(axe);
OCAIS_Axis ax2 = new OCAIS_Axis(Gax2);
OCTopoDS_Shape S2 = new OCBRepPrimAPI_MakeRevol(E, axe, false).Shape();
例3：拓扑线框形成环体
OCTopoDS_Edge E1， E2， E3;
OCTopoDS_Wire W = new OCBRepBuilderAPI_MakeWire(E1, E2, E3).Wire();
OCgp_Ax1 axe = new OCgp_Ax1(new OCgp_Pnt(0, 0, 30), new OCgp_Dir(0, 1, 0));
OCGeom_Axis1Placement Gax3 = new OCGeom_Axis1Placement(axe);
OCAIS_Axis ax3 = new OCAIS_Axis(Gax3);
OCTopoDS_Shape S3 =
new OCBRepPrimAPI_MakeRevol(W, axe, 210 * PI / 180, false).Shape();
1.1.4 OCBRepOffsetAPI_MakePipe
(1) 功能说明：pipe管道
该类建立一个基础Shape（call profile）沿一个线框（call spine--脊骨）扫掠。
Profile不能包含solids;
该类提供如下功能处理：
定义管道的构造，实现构造算法且可查看结果。
注意：该类实现管道的构造仅针对G1连续的spine。
如果是线框应用管道后，变成曲面；如果是面应用管道后，变成体；
(2) 构造函数
public OCBRepOffsetAPI_MakePipe(OCTopoDS_Wire Spine, OCTopoDS_Shape Profile);
(3) 参数说明
Spine:管道的轨迹线；
Profile：沿轨迹线进行扫掠的拓扑SHAPE；
(4) 实例
例1：一个圆面，沿一个曲线（线框）进行扫掠，形成一个SOLID
OCTopoDS_Wire W ;
OCgp_Circ c =
new OCgp_Circ(new OCgp_Ax2(new OCgp_Pnt(0, 0, 0), new OCgp_Dir(0, 1, 0)), 10);
OCTopoDS_Edge Ec = new OCBRepBuilderAPI_MakeEdge(c).Edge();
OCTopoDS_Wire Wc = new OCBRepBuilderAPI_MakeWire(Ec).Wire();
OCTopoDS_Face F = new OCBRepBuilderAPI_MakeFace(Wc, true).Face();
OCTopoDS_Shape S = new OCBRepOffsetAPI_MakePipe(W, F).Shape();
1.1.5 OCBRepOffsetAPI_ThruSections
(1) 功能说明：
Initializes an algorithm for building a shell or a solid passing through a set of sections；
(2) 构造函数
public OCBRepOffsetAPI_ThruSections(bool isSolid, bool ruled, double pres3d)
(3) 参数说明
isSolid：默认值为FALSE;若为真，则表示算法需要建立一个SOLID，否则，表示，需要建立一个SHELL；
ruled：默认值为FALSE; 是否规则
ruled=true： if the faces generated betweenthe edges of two consecutive wires are ruled surfaces;
ruled=false： if they are smoothed out by approximation
pres3d：defines the precision criterion used by the approximation algorithm。默认值为：1.0e-6
(4) 实例
例1：通过四个SECTION形成一个SOLID；
OCgp_Circ c1b =
new OCgp_Circ(new OCgp_Ax2(new OCgp_Pnt(100, 0, -100), new OCgp_Dir(0, 0, 1)), 40);
OCTopoDS_Edge E1b = new OCBRepBuilderAPI_MakeEdge(c1b).Edge();
OCTopoDS_Wire W1b = new OCBRepBuilderAPI_MakeWire(E1b).Wire();
OCgp_Circ c2b =
new OCgp_Circ(new OCgp_Ax2(new OCgp_Pnt(210, 0, -0), new OCgp_Dir(0, 0, 1)), 40);
OCTopoDS_Edge E2b = new OCBRepBuilderAPI_MakeEdge(c2b).Edge();
OCTopoDS_Wire W2b = new OCBRepBuilderAPI_MakeWire(E2b).Wire();
OCgp_Circ c3b =
new OCgp_Circ(new OCgp_Ax2(new OCgp_Pnt(275, 0, 100), new OCgp_Dir(0, 0, 1)), 40);
OCTopoDS_Edge E3b = new OCBRepBuilderAPI_MakeEdge(c3b).Edge();
OCTopoDS_Wire W3b = new OCBRepBuilderAPI_MakeWire(E3b).Wire();
OCgp_Circ c4b =
new OCgp_Circ(new OCgp_Ax2(new OCgp_Pnt(200, 0, 200), new OCgp_Dir(0, 0, 1)), 40);
OCTopoDS_Edge E4b = new OCBRepBuilderAPI_MakeEdge(c4b).Edge();
OCTopoDS_Wire W4b = new OCBRepBuilderAPI_MakeWire(E4b).Wire();
OCBRepOffsetAPI_ThruSections generatorb =
new OCBRepOffsetAPI_ThruSections(true, false, 1.0e-06);
generatorb.AddWire(W1b);
generatorb.AddWire(W2b);
generatorb.AddWire(W3b);
generatorb.AddWire(W4b);
generatorb.Build();
OCTopoDS_Shape S2 = generatorb.Shape();
1.1.6 BRepOffsetAPI_MakePipeShell
说明：
该类提供了一个框架，沿着脊柱的导线构建一个shell或者solid。
构造solid，初始线框必须闭合的。
主要通过两种方法进行定义：
一、截面
二、定义扫掠方式
