I'm pretty open about the development process of . There's source code with a permissive license on github, and I like to post threads about improving the renderer and ideas making it faster and so on. It's a good time.
I use small projects to drive development and post about theme here, too. Right now I've been doing a lot of 3D printing with it, and I've been building a clone of the game Sigmar's Garden to build out the engine's interactive capabilities.