/// <summary>
 /// Constructor from a Grasshopper curve
 /// </summary>
 /// <param name="a">Grasshopper curve</param>
 public RREdge(GH_Curve a)
 {
     this.or = false;
     this.sn = new RRNode(0, a.Value.PointAtStart);
     this.en = new RRNode(0, a.Value.PointAtEnd);
     this.cs = null;
 }
 /// <summary>
 /// Constructor from two nodes
 /// </summary>
 /// <param name="a">First node</param>
 /// <param name="b">Second node</param>
 public RREdge(RRNode a, RRNode b)
 {
     this.or = false;
     this.sn = a;
     this.en = b;
     this.cs = null;
 }
 /// <summary>
 /// Adds new cross section into the list
 /// </summary>
 /// <param name="a">Cross section to add</param>
 public void AddCrCs(RRCrSc a)
 {
     this.csc.Add(a);
 }