Unite 2015 Bezier Mesh yt vid need help with one problem (Tangent ??)

Hello all I am currently working on a bezier curve mesh generator

thanks to this unity unite 2015 video

If you look at the picture attached the blue areas are correct width just the (black circle ) middle for the life in me I can't figure out if
i am a total noobie thanks for any help you can give... View attachment 380833

Code (CSharp):

1. private void createMesh(bool create, bool reset)
2.     {
3.         if (create)
4.         {
5.             t_Pos = new Vector3();
6.             BezierLineBuiltPoints = new List<Vector3>();
7.             points = new List<Vector3>();
8.             Vector3 pts0 = BezierWorldPoints[0].position;
9.             Vector3 pts1 = BezierWorldPoints[1].position;
10.             Vector3 pts2 = BezierWorldPoints[2].position;
11.             Vector3 pts3 = BezierWorldPoints[3].position;
12.  
13.  
14.             for (float t = 0; t <= 1; t += gapSize)
15.             {
16.                 t_Pos = Mathf.Pow(1 - t, 3) * pts0 +
17.                 3 * Mathf.Pow(1 - t, 2) * t * pts1 +
18.                 3 * (1 - t) * Mathf.Pow(t, 2) * pts2 +
19.                 Mathf.Pow(t, 3) * pts3;
20.                 BezierLineBuiltPoints.Add(t_Pos);
21.             }
22.  
23.             //Add last point to finish line
24.             BezierLineBuiltPoints.Add(pts3);
25.  
26.             _linePoints = new Vector3[BezierLineBuiltPoints.Count];
27.             for (int i = 0; i < BezierLineBuiltPoints.Count; i++)
28.             {
29.                 _linePoints[i] = new Vector3(BezierLineBuiltPoints[i].x, BezierLineBuiltPoints[i].y, BezierLineBuiltPoints[i].z);
30.             }
31.  
32.             GameObject tempObj = null;
33.             tempObj = new GameObject("Temp Line Pos");
34.  
35.  
36.             line.positionCount = BezierLineBuiltPoints.Count;
37.             line.SetPositions(_linePoints);
38.             for (var i = 0; i < line.positionCount; i++)
39.             {
40.                 tempObj.transform.position = line.GetPosition(i);
41.                 for (var si = 0; si < shape2d.shapePoints.Count; si++)
42.                 {
43.                     shape2dim = tempObj.transform.position + new Vector3(shape2d.shapePoints[si].x, shape2d.shapePoints[si].y, 0f);
44.                     points.Add(shape2dim);
45.                 }
46.             }
47.             DestroyImmediate(tempObj);
48.  
49.             Vector3[] verticies = new Vector3[points.Count];
50.  
51.             for (int i = 0; i < verticies.Length; i++)
52.             {
53.                 verticies[i] = points[i];
54.             }
55.  
56.             routeSize = line.positionCount - 2;
57.             shapeSize = shape2d.Total_Points - 1;
58.             int[] triangles = new int[shapeSize * routeSize * 6];
59.  
60.             for (int ti = 0, vi = 0, y = 0; y < routeSize; y++, vi++)
61.             {
62.                 for (int x = 0; x < shapeSize; x++, ti += 6, vi++)
63.                 {
64.                     triangles[ti] = vi;
65.                     triangles[ti + 3] = triangles[ti + 2] = vi + 1;
66.                     triangles[ti + 4] = triangles[ti + 1] = vi + shapeSize + 1;
67.                     triangles[ti + 5] = vi + shapeSize + 2;
68.                 }
69.             }
70.             mesh = new Mesh();
71.             mesh.vertices = verticies.ToArray();
72.             mesh.triangles = triangles;
73.             mesh.RecalculateNormals();
74.         }
75.     }

 

nevermind i figured it out was binormals can close this