Majoran

Hi all! I have used sweethome3d some years now, started with a single room interior, then rebuilt a whole flat, rebuilt a four level house and now I'm planning a whole new house - including e.g. electricity cabling - before it will be constructed in real. I am fascinated how all these different applications are still possible with this free software. The only thing I am currently struggling (and even thought about moving to a commercial solution) is handling many many layers: I have currently about...