Revit API射線法讀取空間中相交的元素

Revit API提供根據射線來尋找經過的元素。方法是固定模式，沒什麼好說。
關鍵代碼：[TransactionAttribute(Autodesk.Revit.Attributes.TransactionMode.Manual)]
  FindSupporting : IExternalCommand
{
     Result Execute(ExternalCommandData commandData,   messages, ElementSet elements)
    {

        UIApplication app = commandData.Application;
        Document doc = app.ActiveUIDocument.Document;
        Transaction trans =  Transaction(doc, );
        trans.Start();

        Selection sel = app.ActiveUIDocument.Selection;
                        Reference ref1 = sel.PickObject(ObjectType.Element, );
        Duct duct = doc.GetElement(ref1)  Duct;

                        LocationCurve lc = duct.Location  LocationCurve;
        Curve curve = lc.Curve;
                XYZ ptStart = curve.get_EndPoint();
        XYZ ptEnd = curve.get_EndPoint();

                XYZ offset =  XYZ(, , );        ptStart = ptStart - offset;
        ptEnd = ptEnd - offset;

        View3D view3d = ;
        view3d = doc.ActiveView  View3D;
         (view3d == )
        {
            TaskDialog.Show(, );
             Result.Failed;
        }

         beamLen = curve.Length;
                IList<ReferenceWithContext> references = doc.FindReferencesWithContextByDirection(ptStart, (ptEnd - ptStart), view3d);

        
        sel.Elements.Clear();
         tolerate = ;
         (ReferenceWithContext reference  references)
        {
            Reference ref2 = reference.GetReference();            ElementId id = ref2.ElementId;
            Element elem = doc.get_Element(id);

             (elem  Wall)
            {
                 (reference.Proximity < (beamLen + tolerate))                {
                    sel.Elements.Add(elem);
                }
            }
        }


        trans.Commit();

         Result.Succeeded;
    }
}url:http://greatverve.cnblogs.com/p/FindReferencesWithContextByDirection.html