Open CasCade中的几种类型转换（转）

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_TrimmedCurve
OCC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

例如：

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

gp_Pnt P = BRep_Tool::Pnt(Vertex)
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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