DMG Appendix A

In the last post, I made some analysis of Gygax's Dungeon Geomorphs product. I've also been playing around recently with AD&D DMG Appendix A: Random Dungeon Generation. Let's use the insights to the former product to fill in some of the hidden assumptions in the latter. When using Appendix A, I would highlight or recommend the following:

1. To start with, you should normally begin by going directly to a random room on Table V. (The "Start Areas" on p. 169 are visually arresting, but that's actually a secondary, optional start possibility. You don't want to re-use those a lot.)
2. The tables probably generate more 45-degree passages and 20'-wide corridors than Gygax himself would actually use by default. Be ready to ignore or override those results a lot if they don't fit well into your map; in particular, I make all 45-degree passages automatically 10' wide (ignoring the fact -- as Gygax did -- that running along vertices on the graph paper, they're really just 7' wide).
   
3. Rooms and Chambers (square/rectangular) should, for convenience, always be set up on the cardinal axes -- if accessed off a 45-degree passage, you should probably automatically make them Triangular or Trapezoidal. In addition, all Triangular/Trapezoidal rooms may as well be right-angled, setting them along the grid axes, and giving them a single 45-degree diagonal wall. Any side passage or "door ahead" in a 45-degree corridor should be set along a cardinal-direction, unless it explicitly states the angle at which it should be.
   
4. By default, Rooms should have Doors, and Chambers should have Passages (i.e., non-door openings) as exits. This isn't explicitly stated anywhere, but it's implied in places like Table I (corridors empty into chambers but never rooms), Table II (doors open to rooms 4 times more often than chambers), and Table V-C (result of 19-20 indicates exceptional case of "door in chamber, passage in room").
5. Note that the treasure containment tables (Tables V-H through V-J) are copied verbatim from the earlier Monster & Treasure Assortment product. Tables V-I and V-J (guarded by/hidden in) stand out in Appendix A because they don't have any game statistics associated with the entries. Particularly for solo play, I recommend ignoring these tables (per the "if desired" note -- contrast to Table VII: Trick/Trap, etc.)
6. Also, when making Rooms/Chambers for solo play, I change the generation order to (i) Room shape/size on Table V, (ii) Contents on Table V-F, and last (iii) Exits on Table V-C, etc. This lets any fight be played out before consideration of egress, which cognitively feels better to me (e.g., see the recent discussion on when room size/detail description is appropriate).
7. Note the somewhat unusual secret-door detection rates (by d20) on Table VII, result 1-5. I use this for all indicated secret door checks in Appendix A.
8. Finally, I delete the entry on Table III for "passage X's", since I don't like how it treats cardinal-versus-diagonal passages asymmetrically (i.e., biased towards yet more diagonal passages).
   

Item (3) seems particularly important to me. When using Appendix A in the past, I would tend to get into a diagonal corridor (e.g., Table III actually generates more 45-degree side passages than 90-degree ones), and from that point on I'd be struggling to draw a whole connected region of rectangular rooms, chambers, and passages all diagonal to the graph paper. If you think about it, that really abandons all the advantages to drawing on graph paper in the first place.

If we instead re-set to the cardinal grid every time we enter a room or chamber, then we get more limited diagonal elements, less frustration for DM & players alike, and a dungeon much more like the designs Gygax had in mind when he was laying out maps such as those in the Dungeon Geomorphs and other products.