While working on Get Off My Rock, it became apparent that producing a lot of levels very quickly, in order to test and iterate, would be extremely important. It then fell to me to work out how best to do that.
I’m just going to preface this by saying there are many ways to solve this problem, and mine is just one. I found it extremely hard to find decent documentation on OnSceneGUI, so maybe this’ll help you be a little less stuck than I was! Shout out to The Knights of Unity for this article http://blog.theknightsofunity.com/rendering-custom-gui-scene-view/ which was basically the only thing I managed to find, and was super helpful as a jumping off point.
You can also download the unity package file here to have a play around yourself: GridTutorial