TopoDS_Wire to TopoDS_Edge

Hi,

One solution is to discretize your edges, then interpolate the points with a BSpline, so finally you get a Geom_Curve.
You can take a look at the classes GCPnts_UniformAbscissa, GeomAPI_PointsToBSpline for that purpose.

Another way, if you have a wire that doesn't have discontinuity, is to approximate it using OCC algorithm:

// make your wire looks like a curve to other algorithm
BRepAdaptor_CompCurve wireAdaptor(aWire);
Handle_BRepAdaptor_HCompCurve curve=new BRepAdaptor_HCompCurve(wireAdaptor);

// approximate the curve using a tolerance
Approx_Curve3d approx(curve,0.001,GeomAbs_C2,200,12);
if (approx.IsDone() && approx.HasResult()) {
// have the result
Handle_Geom_Curve anApproximatedCurve=approx.Curve();
}

You should look at cdl files for each of the class to know more about the parameters and limitations.

Good Luck,
Francois.