Dungeon Architect

I had this in Unity for a while. I ported it over to UE4

Select the dungeon actor and go to the Experimental category and enable “Fast Cell Distribution” and specify the dungeon width and length in unreal units. This ignores the NumCells parameter and generates cells (rooms and corridors) inside this [width,length] range

[Edit: This will be available in the next update 2.10.0]

https://i.imgur.com/FW0HdZc.png

https://i.imgur.com/m1FgF7Ph.jpg

This also has better performance for larger dungeons. It works with negation volumes

https://i.imgur.com/MwGMFS2h.jpg

You can create narrower dungeons too

https://i.imgur.com/LRJRPWA.png

https://i.imgur.com/u9BbRK4h.jpg