【图形-OpenCascade】OpenCascade使用

GeomConvert-------  BSpline曲线、曲面拆分，Handle(Geom_Curve)转BSpline曲线

BRepExtrema_DistShapeShape------求两个TopoDS_Shape（TopoDS_Face、TopoDS_Vertex、TopoDS_Edge、TopoDS_Wire...）的最近距离，得到这个距离所对应的点【在TopoDS_Shape1上的和TopoDS_Shape2上的都可以得到】、最近距离的值、最近距离点的个数

GeomAPI_IntCS----求Geom_Curve和Geom_Surface的交点、交点，得到交点的个数和对应的交点、曲线段的条数、对应的曲线（Geom_Curve）

GeomAPI_IntSS----求Geom_Surface和Geom_Surface的交线，得到交线的条数和对应的交线

BRepAlgoAPI_Section---求TopoDS_Shape和TopoDS_Shape、Geom_Surface和TopoDS_Shape、TopoDS_Shape和gp_Pln相交后的数据，得到TopoDS_Shape【包含相交部分的数据，BRepAlgoAPI_Section继承于BRepBuilderAPI_MakeShape】

BRep_Tool---TopoDS_Face转Geom_Surface、TopoDS_Edge转Geom_Curve（转完后可以得到曲线U值范围）、TopoDS_Vertex转gp_Pnt

StlTransfer---TopoDS_Shape转StlMesh_Mesh

StlMesh_MeshExplorer---StlMesh_Mesh的遍历器、获得三角面片的三个顶点的x、y、z值

遍历示例：

 TopoDS_Shape TrimNurbsToSTL( const TopoDS_Face& aTrimTopFace,Standard_Real precision )
 {
	 TopoDS_Face TopoFace = BRepBuilderAPI_MakeFace(aTrimTopFace).Face();
	 Handle_StlMesh_Mesh aSTLMesh = new StlMesh_Mesh();
	 StlTransfer::BuildIncrementalMesh(TopoFace, precision, Standard_False, aSTLMesh);

	 Standard_Integer NumberDomains = aSTLMesh->NbDomains();
	 Standard_Integer iND;
	 gp_XYZ p1, p2, p3;
	 TopoDS_Vertex Vertex1, Vertex2, Vertex3;
	 TopoDS_Face AktFace;
	 TopoDS_Wire AktWire;
	 BRepBuilderAPI_Sewing aSewingTool;
	 Standard_Real x1, y1, z1;
	 Standard_Real x2, y2, z2;
	 Standard_Real x3, y3, z3;

	 aSewingTool.Init(CAD_NURBS_STL_TOLERANCE,Standard_True);

	 TopoDS_Compound aComp;
	 BRep_Builder BuildTool;
	 BuildTool.MakeCompound( aComp );

	 StlMesh_MeshExplorer aMExp (aSTLMesh);

	 for (iND=1;iND<=NumberDomains;iND++) 
	 {
		 for (aMExp.InitTriangle (iND); aMExp.MoreTriangle (); aMExp.NextTriangle ()) 
		 {
			 aMExp.TriangleVertices (x1,y1,z1,x2,y2,z2,x3,y3,z3);
			 p1.SetCoord(x1,y1,z1);
			 p2.SetCoord(x2,y2,z2);
			 p3.SetCoord(x3,y3,z3);

			 if ((!(p1.IsEqual(p2,0.0))) && (!(p1.IsEqual(p3,0.0))))
			 {
				 Vertex1 = BRepBuilderAPI_MakeVertex(p1);
				 Vertex2 = BRepBuilderAPI_MakeVertex(p2);
				 Vertex3 = BRepBuilderAPI_MakeVertex(p3);

				 AktWire = BRepBuilderAPI_MakePolygon( Vertex1, Vertex2, Vertex3, Standard_True);

				 if( !AktWire.IsNull())
				 {
					 AktFace = BRepBuilderAPI_MakeFace( AktWire);
					 if(!AktFace.IsNull())
						 BuildTool.Add( aComp, AktFace );
				 }
			 }
		 }
	 }
	 aSTLMesh->Clear();

	 aSewingTool.Load( aComp );
	 aSewingTool.Perform();
	 TopoDS_Shape aShape = aSewingTool.SewedShape();
	 if ( aShape.IsNull() )
		 aShape = aComp;

	 return aShape;

	
 }

StlMesh_Mesh---获得网格片数、网格面片中的三角面片个数

TopoDS_Shape---存储数据的拓扑结构

TopExp_Explorer---TopoDS_Shape的遍历器

遍历示例;

void example()
{
	TopoDS_Shape aShape;
	TopoDS_Face aFace;
	TopoDS_Wire aWire;
	TopoDS_Edge aEdge;
	TopoDS_Vertex aVertex;
	TopExp_Explorer Exp_Edge;
	TopExp_Explorer Exp_Wire;
	TopExp_Explorer Exp_Face;
	TopExp_Explorer Exp_Vertex;
	for (Exp_Face.Init(aShape,TopAbs_FACE);Exp_Face.More();Exp_Face.Next())
	{
		aFace = TopoDS::Face(Exp_Face.Current());
		for (Exp_Wire.Init(aFace,TopAbs_WIRE);Exp_Wire.More();Exp_Wire.Next())
		{
			aWire = TopoDS::Wire(Exp_Wire.Current());
			for (Exp_Edge.Init(aWire,TopAbs_EDGE);Exp_Edge.More();Exp_Edge.Next())
			{
				aEdge = TopoDS::Edge(Exp_Edge.Current());
				for (Exp_Vertex.Init(aEdge,TopAbs_VERTEX);Exp_Vertex.More();Exp_Vertex.Next())
				{
					aVertex = TopoDS::Vertex(Exp_Vertex.Current());
					gp_Pnt Pnt = BRep_Tool::Pnt(aVertex);
				}
			}
		}
	}
	for (Exp_Vertex.Init(aShape,TopAbs_VERTEX);Exp_Vertex.More();Exp_Vertex.Next())
	{
		aVertex = TopoDS::Vertex(Exp_Vertex.Current());
		gp_Pnt Pnt = BRep_Tool::Pnt(aVertex);
	}
	for (Exp_Edge.Init(aShape,TopAbs_EDGE);Exp_Edge.More();Exp_Edge.Next())
	{
		aEdge = TopoDS::Edge(Exp_Edge.Current());
		Standard_Real First,Last;
		Handle(Geom_Curve) Pnt = BRep_Tool::Curve(aEdge,First,Last);
	}
	for (Exp_Wire.Init(aShape,TopAbs_WIRE);Exp_Wire.More();Exp_Wire.Next())
	{
		aWire = TopoDS::Wire(Exp_Wire.Current());
	}
	for (Exp_Face.Init(aShape,TopAbs_WIRE);Exp_Face.More();Exp_Face.Next())
	{

		aFace = TopoDS::Face(Exp_Face.Current());
		 Handle(Geom_Surface) aSurface = BRep_Tool::Surface(aFace);
	}
}

拓扑创建：

BRepBuilderAPI_MakeVertex = TopoDS_Vertex
BRepBuilderAPI_MakeEdge = TopoDS_Edge
BRepBuilderAPI_MakeWire = TopoDS_Wire
BRepBuilderAPI_MakeFace = TopoDS_Face
BRepBuilderAPI_MakePolygon = TopoDS_Wire //直线框

几何容器：数组队列

TColGeom_xxxxxxxxxxxxxxxxxx

TColgp_xxxxxxxxxxxxxxxxxxxxxx

TColStd_xxxxxxxxxxxxxxxxxxxxx

TDataStd_xxxxxxxxxxxxxxxxxxx