This is a guest post by Patrick Waddingham (Patrick on TT’s GMing Q&A Forum), who won an Honorable Mention for this entry in the Treasure Tables GMing Tools Contest.
– – – – –
Sometimes natural dungeon design can be a pain. Sometimes you just don’t have time. Sometimes your players suddenly decide that they’d rather bash some orc’s face in as opposed to partaking in an epic tale of high fantasy.

That’s fine. If you’re at the table, call a 5 minute timeout. If you’re planning the day before or just don’t have the interest in cavern design, take a deep breath. Either way, try out this neat combination of tricks that anyone can use to make a nifty natural cavern easily and painlessly.

I present to you my tool that I use to design quick natural caverns for actual use and inspiration.

My players leave the table. They go get snacks while I load up Jamis Buck’s Dungeon Generator.

I give it the size and shape I want and hit Print. 30 seconds later I’m given a map, littered with trapped doors, doughnut-shaped hallways, dead-ends, and random objects.

Ack.

So I grab a magic marker and I begin to go to work.

Natural caverns are created by erosion. They don’t set themselves up like a modern city or even like barracks or apartment buildings. This printed map gives you a GREAT foundation for a natural cavern. Now you just have to let your creativity run with it. Using the printed map as a guideline, draw your own dungeon overtop of the rooms given.

(Note: All of the pictures I have included are computer generated, but I made them from the standpoint that someone would be doing this using markers.)

Tada! A quick map for a nice natural cavern, useful for virtually any genre!

This process is very flexible. It is easy to bridge this into other dungeon designs. Perhaps you have an abandoned castle that has seen better days, or a collaped coal mine, or maybe the spaceship went down and uncovered the cavern.

Maybe you came up with an incredible climax within a shrine deep underground, but don’t want to take the time to design every nook-and-cranny around the place yourself. Simply rip out a part or add to the dungeon to include the module you made and call it done.

So what if my players are getting back a little bit late from the break? A dungeon-romp without a point is…well…pointless. So let’s make one!

I grab a random creature chart — the D&D DMG has a few pages dedicated to random monsters according to level — and roll up a few opponents.

I like to get a good mix of monsters (everything from fodder to “Oh man, what was our GM thinking?!?!”). I look at my list, and if something is too outrageous, I toss it. Otherwise I stick it in someplace.

Now, what do all of my new inhabitants think about each other? You don’t have much time to think — your players are settling down at the table talking about the movie they saw the other night.

I use a tip submitted to Roleplaying Tips by David Younce. I reach for a different color of magic marker and I make “relation lines” to particular creatures in the cavern.

Not between all of them, but some of them. Now I roll a d100 for each line drawn. What is this? The line represents that a relationship between the two groups exists, and the number is how well they like each other; 100 being best of friends, 01 being worst of enemies.

Now you can quickly think of why these creatures get along — or perhaps why they don’t.

The drow and the ghouls like each other… Huh… Guess the drow feed them the bodies of the victims they kill. Perhaps they’ll even fight together — or at least ambush the players after they take care of one of the groups.

These two groups of goblins hate each other. Perhaps they’re opposing tribes? Got to be more to it than that. Wonder what the relationships are like around them that would cause them to be at each others throats?

Now you have a neat template for who is in your cavern and why. Perhaps you even have time to gut some things and add in a small shrine, a hidden forge, or whatever else your little GM-heart desires.

There it is, one of my nicest tools. Whether I didn’t plan for an event, or if I just don’t have the inspiration to get going on a dungeon design, this technique has saved me enough times that it makes me wish I could give it a Christmas present. I hope that everyone finds at least a part of this useful.

All you need is:

– – – – –

Thanks, Patrick! What do you think of Patrick’s system? Have you ever used anything like this yourself?