Unity 3D Codes for "Building Tilt Brush from Scratch" YouTube tutorial by Fuseman https://www.youtube.com/watch?v=eMJATZI0A7c
This tutorial is GREAT and Fuseman is super kind to share his knowledge and put this out there. You should watch the video, lots of good stuff in there and it will help you figure out how/where to use this code.
The ONE problem I had with Fuseman's video, there was no link to the custom Unity scripts he was using! I searched everywhere and could not find them, so, I painstakingly screen captured the video and typed each line of code as he had it (spelling errors and all). AND IT WORKS! Follow the video tutorial, and just use these scripts.
He also uses code from Bartek Drozdz so I feel I should mention that (as I don't know who did what, I just transcribed the code!) http://www.everyday3d.com/blog/index.php/2010/03/15/3-ways-to-draw-3d-lines-in-unity3d/
If you are interested in creating your own VR drawing program in Unity, and are frustrated that you cannot find a good code to start with, I hope this will help. It helped me!
NOTE: These codes only cover the "drawing" part of the video, not the color picker part. Feel free to continue if that is your thing.
NOTE: Copy these scripts into your UNITY PROJECTS > "project name" > ASSETS > "folder name you set up in Unity for such things" NOTE: I do not know what the "DrawLineManager.cs.meta" and "GraphicsLineRenderer.cs.meta" files are for, but they were in the Project folder, so I kept them.