LineWeight Display C#

Hi,

I am trying to display polyline geometry via C#.

just want to change the line thickness. Everything is good, when I look from "top view". But when I rotate the camera manually in Rhino Viewport, the displayed geometry is being cut from top and bottom.

How can I solve this issue? I attached image for explanation and grasshopper file.

For display I use following code:

  private void RunScript(Point3d point, ref object A)
  {

    //Calling trail function to limit "pts" list.
    trail();

    //Incrementing point list
    pts.Add(point);

    //Adding points to polyline variable
    pline.Clear();
    pline.AddRange(pts.ToArray());

  }

  // <Custom additional code> 

  //Variables
  List<Point3d> pts = new List<Point3d>();
  Polyline pline = new Polyline();
  int limit = 2550;

  //Function to limit the size of points
  public void trail(){

    if(pts.Count > limit){
      pts.RemoveAt(0);
    }
  }

  //Display
  public override void DrawViewportMeshes(IGH_PreviewArgs args) {
    args.Display.DrawPolyline(pline, Color.Black, 8);
  }