revit api获取excursion 拉伸体的轮廓和平面sketchplane GeometryCreationUtilities

public void GetSketchFromExtrusion()
{
    Document doc = this.ActiveUIDocument.Document;
    Extrusion extrusion = doc.GetElement(new ElementId(3388)) as Extrusion;
    SketchPlane sketchPlane = extrusion.Sketch.SketchPlane;
    CurveArrArray sketchProfile = extrusion.Sketch.Profile;
}