Hi,

I'm having problems making my .Net addin create Intersection Curve between a plane and a solid body.I have already get the Intersection Curve, Furthermore,I want to get the curve parameters of Sketch3DIntersections.my kernel code is below:

RefPlane myRefPlane = null;

                myRefPlane = ((RefPlane)(swDoc.FeatureManager.InsertRefPlane(8, 0.005, 0, 0, 0, 0)));

                swDoc.ClearSelection2(true);

                swDoc.Sketch3DIntersections();

                boolstatus = swDoc.Extension.SelectByID2("", "FACE", 0.015, 0, 0.01, true, 0, null, 0);

                boolstatus = swDoc.Extension.SelectByID2(''datum plane'', "PLANE", 0, 0, 0.05, true, 0, null, 0);

                swDoc.Sketch3DIntersections();

                swDoc.ClearSelection2(true);

                swDoc.SketchManager.InsertSketch(true);//I can get a 3d sketch successfully here

                SketchSegment skSegment2 = null;

                SelectionMgr swSelectMgr = null;

                swSelectMgr = (SelectionMgr)swDoc.SelectionManager;

                skSegment2 = (SketchSegment)swSelectMgr.GetSelectedObject6(1, -1); //step1

                swCurve = (Curve)skSegment2.IGetCurve();

               SplineParamData swSplineParaData = default(SplineParamData);

               swSplineParaData = (SplineParamData)swCurve.GetBCurveParams5(false, false, true, true);

when I go to the step1,It warns me that I can't transform com object“System.__ComObject” to interface “SolidWorks.Interop.sldworks.SketchSegment”,I have seen similiar use in  the API help.so what should I do to get the parameter of the curve?

Best Regards,thanks

Moon