public void GetAndTransformCurve(Autodesk.Revit.ApplicationServices.Application app, 
    Autodesk.Revit.DB.Element element, Options geoOptions)
{
    // Get geometry element of the selected element
    Autodesk.Revit.DB.GeometryElement geoElement = element.get_Geometry(geoOptions);

    // Get geometry object
    foreach (GeometryObject geoObject in geoElement)
    {
        // Get the geometry instance which contains the geometry information
       Autodesk.Revit.DB.GeometryInstance instance = 
           geoObject as Autodesk.Revit.DB.GeometryInstance;
        if (null != instance)
        {
            foreach (GeometryObject o in instance.SymbolGeometry)
            {
                // Get curve
                Curve curve = o as Curve;
                if (curve != null)
                {
                    // transfrom the curve to make it in the instance's coordinate space
                    curve = curve.CreateTransformed(instance.Transform);
                }
            }
        }
    }
}

Public Sub GetAndTransformCurve(app As Autodesk.Revit.ApplicationServices.Application, element As Autodesk.Revit.DB.Element, geoOptions As Options)
    ' Get geometry element of the selected element
    Dim geoElement As Autodesk.Revit.DB.GeometryElement = element.Geometry(geoOptions)

    ' Get geometry object
    For Each geoObject As GeometryObject In geoElement
        ' Get the geometry instance which contains the geometry information
        Dim instance As Autodesk.Revit.DB.GeometryInstance = TryCast(geoObject, Autodesk.Revit.DB.GeometryInstance)
        If instance IsNot Nothing Then
            For Each o As GeometryObject In instance.SymbolGeometry
                ' Get curve
                Dim curve As Curve = TryCast(o, Curve)
                If curve IsNot Nothing Then
                    ' transfrom the curve to make it in the instance's coordinate space
                    curve = curve.CreateTransformed(instance.Transform)
                End If
            Next
        End If
    Next
End Sub