OpenCasCade(九)拓扑运算
1.1.1 拓扑运算描述
1.1.2
BRepAlgoAPI_Cut
(1) 功能说明：布尔差运算
扣除相交部分，并去除CUT SHAPE
(2) 构造函数：
public OCBRepAlgoAPI_Cut(OCTopoDS_Shape S1, OCTopoDS_Shape S2);
public OCBRepAlgoAPI_Cut(OCTopoDS_Shape S1, OCTopoDS_Shape S2, OCBOPTools_DSFiller aDSF, bool bFWD);
(3) 参数说明：
S1：Shape S2 cuts shape S1----被 CUT SHAPE
S2：Shape S2 cuts shape S1----CUT SHAPE
aDSF：布尔运算的数据结构填充器,
BOPTools：Contains main and auxiliary classes to fill the Data Structure (DS) to provide boolean operations between a couple BRep shapes.
包含用于填充一对BRep图形布尔运算的数据结构的主要及辅助的类库。
bFWD：默认值为TURE;
(4) 实例：
OCTopoDS_Shape theSphere = new OCBRepPrimAPI_MakeSphere();
OCTopoDS_Shape theBox = new OCBRepPrimAPI_MakeBox();
OCTopoDS_Shape ShapeCut = new OCBRepAlgoAPI_Cut(theSphere, theBox).Shape()；
1.1.3 BRepAlgoAPI_Fuse
(1) 功能说明：布尔Union运算
运算结果，是两个图形合并
与CUT类同。
1.1.4 BRepAlgoAPI_Section
(1) 功能说明：
计算两个拓扑SHAPE或者两个几何的相交（交集）
可以理解为，由S2切割S1，返回在S1上所切割轨迹。
(2) 构造函数：
//两个几何曲面相交
OCBRepAlgoAPI_Section(OCGeom_Surface Sf1, OCGeom_Surface Sf2, bool PerformNow);
//几何曲面与拓扑SHAPE相交
OCBRepAlgoAPI_Section(OCGeom_Surface Sf, OCTopoDS_Shape Sh, bool PerformNow);
//拓扑SHAPE与几何曲面相交
OCBRepAlgoAPI_Section(OCTopoDS_Shape Sh, OCGeom_Surface Sf, bool PerformNow);
//拓扑SHAPE与几何平面相交
OCBRepAlgoAPI_Section(OCTopoDS_Shape Sh, OCgp_Pln Pl, bool PerformNow);
//两个拓扑SHAPE相交
OCBRepAlgoAPI_Section(OCTopoDS_Shape Sh1, OCTopoDS_Shape Sh2,
bool PerformNow);
//两个拓扑SHAPE相交
OCBRepAlgoAPI_Section(OCTopoDS_Shape S1, OCTopoDS_Shape S2,
OCBOPTools_DSFiller aDSF, bool PerformNow);
(3) 参数说明：
PerformNow：是否立即执行切割动作。默认值为TRUE;
(4) 实例：
例1：用几何平面去切割一个拓扑圆环SHAPE,并返回圆环上的切割轨迹（红色部分）
OCTopoDS_Shape theTorus = new OCBRepPrimAPI_MakeTorus(35, 8).Shape();
OCgp_Pln aplane = new OCgp_Pln(1, 0.25, 3, 4);
OCGeom_Plane thePlane = new OCGeom_Plane(aplane);
OCBRepAlgoAPI_Section section =
new OCBRepAlgoAPI_Section(theTorus, thePlane, false);
section.ComputePCurveOn1(true);
section.Approximation(true);
section.Build();
OCAIS_Shape asection = new OCAIS_Shape(section.Shape());
1.1.5 BRepAlgoAPI_Common
(1) 功能说明：布尔Intersection运算
运算结果为两个图形相交部分
与CUT类同。
1.1.6 BRepFeat_SplitShape
说明：
实例：
(1) 曲面拆分
bool DoSplit(OCTopoDS_Shape aS1, OCTopoDS_Shape aS2)
{
OCBRepAlgoAPI_Section sec = new OCBRepAlgoAPI_Section(aS1, aS2, false);
sec.ComputePCurveOn1(true);
sec.Approximation(true);
sec.Build();
OCTopoDS_Shape aInterCurve = sec.Shape();
OCTopoDS_Face aFace = OCTopoDS.Face(aS1);
OCBRepFeat_SplitShape ssplit = new OCBRepFeat_SplitShape(aS1);
OCTopExp_Explorer ex = new OCTopExp_Explorer();
for (ex.Init(aInterCurve, OCTopAbs_ShapeEnum.TopAbs_EDGE, OCTopAbs_ShapeEnum.TopAbs_SHAPE); ex.More(); ex.Next())
{
OCTopoDS_Edge aE = OCTopoDS.Edge(ex.Current());
OCTopoDS_Shape aF = new OCTopoDS_Shape();
if (sec.HasAncestorFaceOn1(aE, aF))
{
OCTopoDS_Face aAncFace = OCTopoDS.Face(aF);
if (aAncFace.IsSame(aFace))
ssplit.Add(aE, aFace);
}
}
ssplit.Build();
OCTopTools_ListOfShape shapeList = ssplit.Modified(aFace);
OCTopTools_ListIteratorOfListOfShape ite = new OCTopTools_ListIteratorOfListOfShape(shapeList);
for (; ite.More(); ite.Next())
{
OCTopoDS_Shape aS = ite.Value();
OCAIS_Shape aiss = new OCAIS_Shape(aS);
context.Display(aiss, true);
}
return true;
}
1.1.7 BRepFeat_MakePipe
基类为：BRepFeat_Form；
通过基本图形生成一个Pipe;
1.1.8 BRepFeat_MakeLinearForm
基类为：BRepFeat_RibSlot
在一个平面表面上建一个肋或开凹槽；
1.1.9 BRepFeat_Gluer
