I'm currently reading a book called 'Creating the Art for the Game' which I must admit has told me things that I would never imagine involved in games. My problem is, understanding Vertex colouring and its purposes, the book uses and example of making a glass 'cup' transparant by basically using no material or shader but by painting the vertex colouring and giving them a transparancy. What are other uses for this method? Any explainations would be great.

Cheers guys