How to make a Linediagram

There are multiple ways of drawing lines in Unity, all with their specific issues. If you don't mind spending money, the Vectrosity package is by far the most complete solution. Other solutions:

• LineRenderer

• Drawing a custom mesh

• Use of GL class

• Use of 3D objects like a cylinder or a Quad

Here is an old Blog that goes into more detail on three of them.

http://www.everyday3d.com/blog/index.php/2010/03/15/3-ways-to-draw-3d-lines-in-unity3d/comment-page-1/