Create 3DSweep

 //  Profile of the
        static List<XYZ> _profilepoints = new List<XYZ>()
        {
            new XYZ (-0.082020997, 0.000000000, 0.000000000),
            new XYZ(0.410104987, 0.000000000, 0.000000000),
            new XYZ (-0.082020997, 0.984251969, 0.000000000),
            new XYZ (-0.082020997, 0.000000000, 0.000000000),
            new XYZ (0.246062992, 0.984251969, 0.000000000),
            new XYZ(-0.082020997, 0.984251969, 0.000000000),
            new XYZ (0.410104987, 0.000000000, 0.000000000),
            new XYZ(0.410104987, 0.820209974, 0.000000000),
            new XYZ (0.246062992, 0.984251969, 0.000000000),
            new XYZ(0.410104987, 0.820209974, 0.000000000)
      };



static public Document m_doc;

        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
        {
            UIApplication uiapp = commandData.Application;
            UIDocument uidoc = uiapp.ActiveUIDocument;
            m_doc = uidoc.Document;

            IList<Reference> refs = null;
            refs = uidoc.Selection.PickObjects(ObjectType.Edge);

            Transaction tr = new Transaction(m_doc, "curvemodel");
            tr.Start();

            ReferenceArray rArr = new ReferenceArray();


            foreach (Reference r in refs)
            {
                Options op = new Options();
                op.ComputeReferences = true;

                Element e = m_doc.GetElement(r.ElementId);

                GeometryElement ge = e.get_Geometry(op);
                foreach (GeometryObject go in ge)
                {
                    Solid solid = go as Solid;
                    foreach (Edge edg in solid.Edges)
                    {
                        if (edg.Reference.ConvertToStableRepresentation(m_doc) == r.ConvertToStableRepresentation(m_doc))
                        {



                            SketchPlane plan = SketchPlane.Create(m_doc, edg.GetFace(0).Reference);

                            ModelCurve mc = m_doc.FamilyCreate.NewModelCurve(edg.AsCurve(), plan);

                            rArr.Append(mc.GeometryCurve.Reference);


                        }

                    }
                }



            }
            tr.Commit();

            Transaction t = new Transaction(m_doc, "Create Sweep2d");
            t.Start();

            createcurbs(m_doc, rArr);       //Create 3D sweep

            t.Commit();

 return Result.Succeeded;

        }


///3Dsweep Method
        public void createcurbs(Document doc, ReferenceArray path3D)
        {
            FamilyItemFactory factory = doc.FamilyCreate;


            IList<Curve> cel = new List<Curve>();

            for (int i = 0; i < _profilepoints.Count; i = i + 2)
            {
                try
                {
                    cel.Add(Line.CreateBound(_profilepoints[i], _profilepoints[i + 1]) as Curve);

                }
                catch (Exception)
                {

                    cel.Add(Line.CreateBound(_profilepoints[i], _profilepoints[0]) as Curve);

                }


            }

            CurveArray sweepArray = DrawLoops.convert2Array(cel);  //method to arrange Curves inorder to create a contiguous loop and then convert it to Array


            CurveArrArray swerarar = new CurveArrArray();
            swerarar.Append(sweepArray);

            SweepProfile swpprof = doc.Application.Create.NewCurveLoopsProfile(swerarar);       // this is the profile



            // Create sweep solid

            Sweep sweep3D = factory.NewSweep(true, path3D, swpprof, 0, ProfilePlaneLocation.Start);


    }

    }
 }