Google Design Guidelines for Google Cardboard
One of the first things I did when I started this project’s research was to look at the existing R&D that was done by reliable sources. I think I’m not far off when I say there’s no better source of R&D than Google. So I had to look at everything Google made public. And I found a gold mine.
The site served as a great starting point and gave really valuable inputs, from practical aspects such as how you should set up Android for VR, to the Physiological considerations that are to be kept in mind while working on any VR development.
Things such as head tracking, movement speed in Virtual Reality, brightness changes, etc are discussed in detail and these insights lay the ground work pretty well.