Daylight's Procedural Generation - How Was It Done?

Hello all! I’ve been looking for this forever and haven’t found anything so, does anyone have an idea of how Daylight’s procedural generation was done? I’ve been trying to do something similar for a while but I could never get it right. I have modular assets of which module consists. Each module is a blueprint. What I want to do is arrange them similar to how Daylight does it. Anyone have an idea?