# File structures/Boundaries.rb, line 83
  def addKnot(u)
    p,cp1,cp2,i = @spline.evaluateFull(u)
    newD = [@spline.d.slice(1..i),cp1,cp2,@spline.d.slice((i+2)..(@spline.d.length-2))].flatten
    newK = [@spline.k.slice(0..i),u,@spline.k.slice((i+1)..(@spline.k.length-1))].flatten
    #puts newK.join(",")
    if @spline.closed
      @spline = QBSpline.new(newD, true,newK)
    else
      points = [@spline.d.first, newD, @spline.d.last].flatten
      @spline = QBSpline.new(points,false,newK)
    end
  end