void  CirclePy::setYAxis(Py::Object arg)
{
    PyObject* p = arg.ptr();
    Base::Vector3d val;
    if (PyObject_TypeCheck(p, &(Base::VectorPy::Type))) {
        val = static_cast<Base::VectorPy*>(p)->value();
    }
    else if (PyTuple_Check(p)) {
        val = Base::getVectorFromTuple<double>(p);
    }
    else {
        std::string error = std::string("type must be 'Vector', not ");
        error += p->ob_type->tp_name;
        throw Py::TypeError(error);
    }

    Handle_Geom_Circle circle = Handle_Geom_Circle::DownCast(getGeomCirclePtr()->handle());
    try {
        gp_Ax2 pos;
        pos = circle->Position();
        pos.SetYDirection(gp_Dir(val.x, val.y, val.z));
        circle->SetPosition(pos);
    }
    catch (Standard_Failure) {
        throw Py::Exception("cannot set Y axis");
    }
}
int convert_to_ifc(const Handle_Geom_Curve& c, IfcSchema::IfcCurve*& curve, bool advanced) {
	if (c->DynamicType() == STANDARD_TYPE(Geom_Line)) {
		IfcSchema::IfcDirection* d;
		IfcSchema::IfcCartesianPoint* p;

		Handle_Geom_Line line = Handle_Geom_Line::DownCast(c);

		if (!convert_to_ifc(line->Position().Location(), p, advanced)) {
			return 0;
		}
		if (!convert_to_ifc(line->Position().Direction(), d, advanced)) {
			return 0;
		}

		IfcSchema::IfcVector* v = new IfcSchema::IfcVector(d, 1.);
		curve = new IfcSchema::IfcLine(p, v);

		return 1;
	} else if (c->DynamicType() == STANDARD_TYPE(Geom_Circle)) {
		IfcSchema::IfcAxis2Placement3D* ax;

		Handle_Geom_Circle circle = Handle_Geom_Circle::DownCast(c);

		convert_to_ifc(circle->Position(), ax, advanced);
		curve = new IfcSchema::IfcCircle(ax, circle->Radius());

		return 1;
	} else if (c->DynamicType() == STANDARD_TYPE(Geom_Ellipse)) {
		IfcSchema::IfcAxis2Placement3D* ax;

		Handle_Geom_Ellipse ellipse = Handle_Geom_Ellipse::DownCast(c);

		convert_to_ifc(ellipse->Position(), ax, advanced);
		curve = new IfcSchema::IfcEllipse(ax, ellipse->MajorRadius(), ellipse->MinorRadius());

		return 1;
	}
#ifdef USE_IFC4
	else if (c->DynamicType() == STANDARD_TYPE(Geom_BSplineCurve)) {
		Handle_Geom_BSplineCurve bspline = Handle_Geom_BSplineCurve::DownCast(c);

		IfcSchema::IfcCartesianPoint::list::ptr points(new IfcSchema::IfcCartesianPoint::list);
		TColgp_Array1OfPnt poles(1, bspline->NbPoles());
		bspline->Poles(poles);
		for (int i = 1; i <= bspline->NbPoles(); ++i) {
			IfcSchema::IfcCartesianPoint* p;
			if (!convert_to_ifc(poles.Value(i), p, advanced)) {
				return 0;
			}
			points->push(p);
		}
		IfcSchema::IfcKnotType::IfcKnotType knot_spec = opencascade_knotspec_to_ifc(bspline->KnotDistribution());

		std::vector<int> mults;
		std::vector<double> knots;
		std::vector<double> weights;

		TColStd_Array1OfInteger bspline_mults(1, bspline->NbKnots());
		TColStd_Array1OfReal bspline_knots(1, bspline->NbKnots());
		TColStd_Array1OfReal bspline_weights(1, bspline->NbPoles());

		bspline->Multiplicities(bspline_mults);
		bspline->Knots(bspline_knots);
		bspline->Weights(bspline_weights);

		opencascade_array_to_vector(bspline_mults, mults);
		opencascade_array_to_vector(bspline_knots, knots);
		opencascade_array_to_vector(bspline_weights, weights);

		bool rational = false;
		for (std::vector<double>::const_iterator it = weights.begin(); it != weights.end(); ++it) {
			if ((*it) != 1.) {
				rational = true;
				break;
			}
		}

		if (rational) {
			curve = new IfcSchema::IfcRationalBSplineCurveWithKnots(
				bspline->Degree(),
				points,
				IfcSchema::IfcBSplineCurveForm::IfcBSplineCurveForm_UNSPECIFIED,
				bspline->IsClosed(),
				false,
				mults,
				knots,
				knot_spec,
				weights
				);
		} else {
			curve = new IfcSchema::IfcBSplineCurveWithKnots(
				bspline->Degree(),
				points,
				IfcSchema::IfcBSplineCurveForm::IfcBSplineCurveForm_UNSPECIFIED,
				bspline->IsClosed(),
				false,
				mults,
				knots,
				knot_spec
				);
		}

		return 1;
	}
#endif
	return 0;
}