Watching programmes about design makes you think about design, and in my case, dungeon design. There are lots of blog posts and other resources out there about how to make dungeons, and some of them are truly excellent. (Benoist's series on The RPG Site is the best of them.) There are interesting and innovative ideas about specific tasks such as keying (like the Dungeon Shorthand). There are thoughtful discusses at the level of principle (like Philotomy's Musings). But I don't think I've ever come across anything that is specifically about the design of a dungeon at the level of actually drawing it. When you sit down with a blank piece of paper, how do you actually draw a good dungeon level? How do you arrange the rooms and corridors to best effect? Where you do put the entrance and exit? Where do you put the traps and treasure? (Assuming you aren't random-stocking?)
So, let's think about it. You will have your own opinions which you are free to post here, or elsewhere. But here are some for starters. (Note: I almost never stick to these myself, but whenever I don't, I regret it.)
1. Rebuttable Preference for NSEW
Snazzy weird shapes and arrangements of rooms look good on paper but in my experience are really hard to explain at the table without ending up with the DM doing lots of drawing, which defeats the purpose of having players do the mapping. For this reason, I have a very strong preference for rooms which are basically rectangular or square (circles and hexagons are less good but okay; triangles are difficult; anything else is a pain). Similarly, I much prefer exits to be identifiable as a cardinal direction, and ditto for corridors to go in those directions. ("The corridor goes north," is so much simpler than "The corridor goes straight ahead for a bit, and then sort of bends to the left, and then corrects itself, and then bends left again...")
2. Symmetry is Lazy
It's easy to fall back on symmetry when you're having difficulty thinking. I'm sure you've all experienced this: you've drawn part of a dungeon and you're getting tired and so you do the DMing equivalent of a rorshach print and effectively fold it back on itself so you get twice as much bang for your buck, with one half of the page mirroring the other. This, in my experience, tends towards the drab, but also leads your imagination down a bit of a cul-de-sac - better to be expansive and keep sections of dungeon asymmetrical. (It's also somewhat unrealistic - architecture is rarely if ever symmetrical in real buildings.)
3. It's All About Connectivity
Perhaps the most important thing is connectivity. Compare Fig. 2 with Fig. 3 below.
Fig. 2 may have lots of rooms and a relatively complex layout but there are very few options for exploration - it is basically a railroad. At times PCs can go on detours, but these always lead to them having to retrace their steps, and their travel through the dungeon is ultimately limited to describing a glorified circle. This is bad.
Fig. 3 on the other hand is the same map but with connecting corridors added. Suddenly there are lots of options for the PCs when exploring, and also excuses for monsters in different parts of the dungeon to interact with each other. The PCs can actually interact with the map, once they've explored it, by taking shortcuts and setting up ambushes.
These maps are small and simple (and I have over-done things with Fig. 3 to make a point) but the principle is just as important in a dungeon with 100 rooms. Connectivity makes the experience richer for both DM and players.
4. Speed-Bump, Barrier, or Deflector
From the perspective of PC movement, just about anything you can place in a dungeon that isn't treasure will be one of three things: a speed-bump, a barrier, or a deflector. Any monster, trap, puzzle or NPC has the potential to either:
- Slow things down briefly (pause to kill some goblins or rescue the dwarf from the pit trap; resume)
- Prevent progress entirely (big scary dragon or pit of level-draining ghost vipers is too dangerous; PCs don't move past it and hence an area of the dungeon is closed off until they can)
- Deflect travel in a different direction (NPC tells the PCs about treasure in a certain room, puzzle leads to secret door, etc.)
This is worth considering when placing items in the dungeon after the rooms are mapped out. Anything you put anywhere will have one of those effects.