1. 将Geom_BSplineSurface转化成TopoDS_Face：

Handle_Geom_BSplineSurface BSurface;BRep_Builder builder;TopoDS_Face Face;builder.MakeFace(Face,BSurface,Tolerance);2.将TopoDS_Face 转化为Geom_Surface：

Handle_Geom_Surface currentSur;TopExp_Explorer Ex; Ex.Init(shape,TopAbs_FACE); TopoDS_Face currentVt = TopoDS::Face(Ex.Current());currentSur = BRep_Tool::Surface(currentVt);3.普通曲线转化为NURBS曲线：

Handle(Geom_Curve) ResCurve ;Handle(Geom_TrimmedCurve) myTrimmed = new Geom_TrimmedCurve(ResCurve, 0, 1);NurbsCurve = GeomConvert::CurveToBSplineCurve(myTrimmed); //必须指定曲线的类型如Geom_TrimmedCurveOCC的说明如下：

— Purpose : This function converts a non infinite curve from

— Geom into a B-spline curve.C must be an ellipse or a

— circle or a trimmed conic or a trimmed line or a Bezier

— curve or a trimmed Bezier curve or a BSpline curve or a

— trimmed BSpline curve or an OffsetCurve. The returned B-spline is

— not periodic except if C is a Circle or an Ellipse.

4. Geom_Surface 转 Geom_BsplineSurface

GeomConvert::SurfaceToBSplineSurface(surface)其中surface必须为Geom_Surface 中的某一具体类型

OCC的说明如下：

— Purpose : This algorithm converts a non infinite surface from Geom

— into a B-spline surface.

— S must be a trimmed plane or a trimmed cylinder or a trimmed cone

— or a trimmed sphere or a trimmed torus or a sphere or a torus or

— a Bezier surface of a trimmed Bezier surface or a trimmed swept

–surfacewith a corresponding basis curve which can be turned into

— a B-spline curve

5. 点云转 Geom_BsplineSurface

Handle_Geom_BSplineSurface CMiniCADTool::BuildSurface(const TColgp_SequenceOfXYZ& seqOfXYZ) { // Build the surface: // points are projected on plane z = 0 // the projection vector for each point is computed // These data give the input constraints loaded into plate algorithm const Standard_Integer nbPnt = seqOfXYZ.Length(); Standard_Integer i; //Filling plate Plate_Plate myPlate; for (i=1; i<= nbPnt; i += 4) { gp_Vec aVec(0., 0., seqOfXYZ.Value(i).Z()); gp_XY pntXY(seqOfXYZ.Value(i).X(),seqOfXYZ.Value(i).Y()); Plate_PinpointConstraint PCst( pntXY,aVec.XYZ() ); myPlate.Load(PCst); // Load a pinpoint constraint } myPlate.SolveTI(2, 1.); // Solving plate equations if (!myPlate.IsDone()) { return Handle(Geom_BSplineSurface)(); } // Computation of plate surface gp_Pnt Or(0,0,0.); gp_Dir Norm(0., 0., 1.); Handle(Geom_Plane) myPlane = new Geom_Plane(Or, Norm);// Plane of normal Oz Handle(GeomPlate_Surface) myPlateSurf = new GeomPlate_Surface(myPlane, myPlate);//plate surface GeomPlate_MakeApprox aMKS(myPlateSurf, Precision::Approximation(), 4, 7, 0.001, 0);//bspline surface return aMKS.Surface(); } 6.surface 向Geom_Plane 向下转换（DownCast方法）其中Geom_Plane类中有方法可以将gp_Pln和Geom_Plane进行相互转化。

Handle(Geom_Plane) aPlane = Handle(Geom_Plane)::DownCast(BRep_Tool::Surface(SelectFace));PlaneOfTheView = aPlane->Pln(); 7.TopoDS_Shape 向相应的格式转

Vertex = TopoDS::Vertex(Shape);8.TopoDS_Vertex向gp_Pnt转

gp_Pnt P = BRep_Tool::Pnt(Vertex)————————————————版权声明：本文为CSDN博主「醉逍遥_祥」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。原文链接：https://blog.csdn.net/qq_35097289/article/details/103816707

————————

1. 将Geom_BSplineSurface转化成TopoDS_Face：

Handle_Geom_BSplineSurface BSurface;BRep_Builder builder;TopoDS_Face Face;builder.MakeFace(Face,BSurface,Tolerance);2.将TopoDS_Face 转化为Geom_Surface：

Handle_Geom_Surface currentSur;TopExp_Explorer Ex; Ex.Init(shape,TopAbs_FACE); TopoDS_Face currentVt = TopoDS::Face(Ex.Current());currentSur = BRep_Tool::Surface(currentVt);3.普通曲线转化为NURBS曲线：

Handle(Geom_Curve) ResCurve ;Handle(Geom_TrimmedCurve) myTrimmed = new Geom_TrimmedCurve(ResCurve, 0, 1);NurbsCurve = GeomConvert::CurveToBSplineCurve(myTrimmed); //必须指定曲线的类型如Geom_TrimmedCurveOCC的说明如下：

— Purpose : This function converts a non infinite curve from

— Geom into a B-spline curve.C must be an ellipse or a

— circle or a trimmed conic or a trimmed line or a Bezier

— curve or a trimmed Bezier curve or a BSpline curve or a

— trimmed BSpline curve or an OffsetCurve. The returned B-spline is

— not periodic except if C is a Circle or an Ellipse.

4. Geom_Surface 转 Geom_BsplineSurface

GeomConvert::SurfaceToBSplineSurface(surface)其中surface必须为Geom_Surface 中的某一具体类型

The description of OCC is as follows:

— Purpose : This algorithm converts a non infinite surface from Geom

— into a B-spline surface.

— S must be a trimmed plane or a trimmed cylinder or a trimmed cone

— or a trimmed sphere or a trimmed torus or a sphere or a torus or

— a Bezier surface of a trimmed Bezier surface or a trimmed swept

–surfacewith a corresponding basis curve which can be turned into

— a B-spline curve

5. 点云转 Geom_BsplineSurface

Handle_Geom_BSplineSurface CMiniCADTool::BuildSurface(const TColgp_SequenceOfXYZ& seqOfXYZ) { // Build the surface: // points are projected on plane z = 0 // the projection vector for each point is computed // These data give the input constraints loaded into plate algorithm const Standard_Integer nbPnt = seqOfXYZ.Length(); Standard_Integer i; //Filling plate Plate_Plate myPlate; for (i=1; i<= nbPnt; i += 4) { gp_Vec aVec(0., 0., seqOfXYZ.Value(i).Z()); gp_XY pntXY(seqOfXYZ.Value(i).X(),seqOfXYZ.Value(i).Y()); Plate_PinpointConstraint PCst( pntXY,aVec.XYZ() ); myPlate.Load(PCst); // Load a pinpoint constraint } myPlate.SolveTI(2, 1.); // Solving plate equations if (!myPlate.IsDone()) { return Handle(Geom_BSplineSurface)(); } // Computation of plate surface gp_Pnt Or(0,0,0.); gp_Dir Norm(0., 0., 1.); Handle(Geom_Plane) myPlane = new Geom_Plane(Or, Norm);// Plane of normal Oz Handle(GeomPlate_Surface) myPlateSurf = new GeomPlate_Surface(myPlane, myPlate);//plate surface GeomPlate_MakeApprox aMKS(myPlateSurf, Precision::Approximation(), 4, 7, 0.001, 0);//bspline surface return aMKS.Surface(); } 6.surface 向Geom_Plane 向下转换（DownCast方法）其中Geom_Plane类中有方法可以将gp_Pln和Geom_Plane进行相互转化。

Handle(Geom_Plane) aPlane = Handle(Geom_Plane)::DownCast(BRep_Tool::Surface(SelectFace));PlaneOfTheView = aPlane->Pln(); 7.TopoDS_Shape 向相应的格式转

For example:

Vertex = TopoDS::Vertex(Shape);8.TopoDS_Vertex向gp_Pnt转

gp_ Pnt P = BRep_ Tool:: pnt (vertex) ——————————————————————————————————————————————————————————————————————————————-. Original link: https://blog.csdn.net/qq_35097289/article/details/103816707