I'm now referring to it as a giga-dungeon.![]()
I recommend some of the other things mentioned already of course - such as drawing it out on graph paper.
But, Google Sketch is a free 3d program you might try (very easy to use). I made the following very quickly...
[edit] Download it here [/edit]
Thank you so much for mentioning this program. I think this is what I have been looking for for years
Havard