Came up with a simple concept for generating 3D generated dungeons. It works by the following steps:
1.Generate a grid of any size
2.Randomly place room of random sizes on the grid (red squares)
3.Pathfind to every single room leaving a trail of red squares
4.Create a border of walls round the red squares
5.Put the player in a 3D world.
Full video here - youtu.be/r4VHEksCev4