Megadungeon Monday: Mapsturbation and the Size of Encounters

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Happy Megadungeon Monday!

If you’re expecting more maps, you’re going to be disappointed for seven more days. Sorry. But if you’re using this series to help you design your own thing, today will be very important for you. Because we have to talk ABOUT maps before we can draw some map. And don’t worry. The last time I said that, we ended up with six weeks of spreadsheet overanalysis. This is just a self-contained little discussion that will help us start mapping.

We began last week trying to figure out how we can figure out the layout a massive, sprawling dungeon complex with two hundred rooms and make it all fit together and to be consistent. And we came up with the idea of starting with a flowchart and gradually snapping it to finer and finer grids. And honestly, that technique is a good one even if your dungeon has fifty rooms. Or ten.

And so we made a template that roughly represented the shape and size of the overall space and started dropping blobby little encounter days on it and connecting them all up. And in so doing, we translated both the mechanical and the narrative plot into a flowchart that will serve as the basis for the map.

The NEXT step will be to expand each of those vague blobby “adventure days” into vague blobby interconnected “encounter spaces.” And we COULD do it as a flowchart thing again. But if we do that, when we turn each little blobs into an encounter space for reals, some of them will be big and some will be small and it we might end up running out of room.

Plan Ahead

So, unlike a physicist whose solution only works for a spherical chicken in a vacuum (look it up), we’re not going to assume our encounters are point-like particles floating in a vague dungeon space. We’re going to give them size right now. At the very least, we’re going to give each one a sort of outer boundary. As we draw our encounter spaces, we’re going to decide how big is the biggest they can be. On a per encounter basis. That is, we’re going to decide DS001 is about 50 feet by 50 feet. It might be 50 feet by 45 feet when we’re done and it might be an L-shaped room. But it won’t be BIGGER than 50 feet by 50 feet. And it won’t be much smaller either.

But to do that, we need to answer a question: how big is an encounter? And to answer that, we should probably figure out why we’re even bothering with a map. Why? Partly because I like thinking about dumb questions like “why do maps exist” or “why is there air?” And partly because when you apply critical thought to something that SEEMS simple, often it leads you to think about the problem in new ways and find better solutions. And that is why, whenever you are faced with a conundrum, the best thing you can do is start by answering the biggest, dumbest question that is most obviously a non-issue.

Why Are There Maps?

Why do we have maps for these games? Let’s start with the obvious. Maps tell you where the players end up when they go through that door. A map is essentially a diagram of the scenes of an adventure and the transitions between them. It’s far easier to comprehend a map than it is to parse that from text. And honestly, that’s no different from a flowchart or timeline in other types of adventure. Maps are diagrams of a site-based adventure. A flowchart is a diagram of a more general type of exploration encounter. And a timeline is a diagram of an event-based or time-based encounter.

But is that the whole answer? After all, maps are hard to draw. They take resources. You have to hire a cartographer. It takes up space in your book that could be used for words. And yet, I’ve seen maps in adventures that weren’t about exploring physical spaces. For example, I’ve seen maps of entire houses or mills or inns in mystery adventures in which one room of the space actually contains information. WHY?

Well, it could be that maps are also pictures and pictures convey useful information. Beyond all the “joining up physical spaces,” depending on things like color palette and all the little details and embellishments, maps can convey atmosphere and mood. They can help communicate intangible things about the space that would be difficult in words. A dark color palette, a few cobwebs in the corner, and a strange greenish puddle, and suddenly this generic underground hallway is now a sinister catacomb whose flagstones have not seen the trod of a human boot in countless ages.

But THEN, there are maps that don’t have any of that crap. I’ve seen maps that were just line drawings. No detail at all other than “room 32 is 20 feet by 30 feet and has a door in the north and one in the south.” Hell, I’ve seen event-based encounters with those sorts of maps. And then you have some pretty famous cartographers whose style is always the same. Their maps always convey the same mood: “this is a I map that I, famous cartographer Alice Bobbington, drew.”

So why are there maps? Why are maps so ubiquitous that every role-playing game product has a bunch of them, regardless of the purpose they serve or don’t serve. Well, here’s a big ole clue: maps are for GMs. Most players never see the maps in most RPG products. Even if the GM is using a battlemat or dungeon tiles or painted terrain or whatever, the players aren’t seeing the big gorgeous map in the book. They see the GM’s clumsy attempts at recreating it. And that will ALWAYS rob it of the mood, the ambiance, and any details that don’t have a direct mechanical impact. That puddle? If it doesn’t slow movement or attack people, the GM isn’t drawing it on the battle grid.

The answer is: maps are porn for GMs. Seriously. In an adventure called Sex Slaves of Castle Lustnymph in which the heroes have to rescue bondage slaves of every race and gender, all of whom are VERY grateful, if you want it to sell, skip the illustrator and hire the best cartographer you can. GMs don’t care about boobies or wangs unless they can put them on a 5-foot by 5-foot grid.

Also, head on over to Drive Thru RPG right now to buy my new product “Sex Dungeons of Castle Lustnymph: The Complete Map Pack.” Hurry, before they ban it… oops. Too late. Sorry. But it’s good that we have gatekeepers, otherwise you’d be at risk at being able to enjoy your hobby any way you wanted in the privacy of your own home.

But I digress. In the end, maps exist because GMs like maps. Even when they are unnecessary. But they can convey mood and ambiance and are as much a part of the presentation of the product as the art and the layout and words. And in adventures based on the exploration of physical spaces, maps serve as a diagram of where the PCs can go and what they can do when they get there.

But Combat Encounters!

Right. Right. You might be tempted to think that maps are necessary because the combat rules of D&D and Pathfinder (and some other games) demand that everyone keep track of who’s next to who and how far you can move and the range and areas of certain spells. And you’d be right. But you’d also be wrong. That doesn’t actually demand maps.

Imagine I have a dungeon with three rooms. The first is a guard post, where the PCs fight guard monsters. Then, there’s a long tunnel. Then, the second room has a ravine that is 50’ feet wide and a dangerous rope bridge the PCs have to cross carefully. Then, another long tunnel, and then there’s a boss room where the PCs have to fight a boss monster.

I don’t need a map of that dungeon. I need a schematic of the first and third room, because that’s where the fights happen. And that’s it. COMBAT ENCOUNTERS do not need maps. Nothing that a map does (diagram of the plot, ambiance, gamemasterburation) has anything to do with an encounter map. Even though we call it a map. It’s really more of a schematic.

This might seem like a really subtle distinction, but it can actually save a bunch of GMs a lot of work. The fact is, unless you plan to have a combat encounter in every room, you really DON’T need to stick your dungeon on a grid. With a vague discussion on how to track the passage of time in one sidebar of your adventure, you could dispense with the graph paper, the concept of levels lining up, and all the other crap that 4-squares per inch bring with them. You could just design a pretty map and expand the areas that need it into encounter schematics.

Of course, I can’t do ANY of that. Because, first of all, most of the spaces in this dungeon will have combat encounters. We decided that way back at the beginning. This is an old-school action dungeon. And because we’re using wandering monster and backfilling mechanics, even if a room doesn’t have a combat in it to begin with, that doesn’t mean it won’t suddenly be filled with kruthiks or skeletons or elemental demon-beasts later on.

And that means that no, we can’t get away with porn maps. We need grid maps. Real grid maps. The whole dungeon needs a f$&%ing grid. And every space should be designed with combat in mind.

How Big is a Battle?

And that brings us around to the question we need to answer before we start drawing: how big is a combat encounter.

For simplicity, even though it pisses off the people who never forgave D&D 4E because it ruined D&D and it was World of Warcraft and it killed orphan puppies and dragons had boobs, we’re going to talk in terms of squares. A square is a grid-space that is 5-foot by 5-foot. It is the space taken up by a small or medium sized creature on the grid. And 5 feet is the standard measure for movement, range, and pretty much everything in D&D and Pathfinder. And since we’re going to be working on graph paper anyway, we might as well just figure out, in terms of squares, how much space an encounter needs.

Let’s start with the simplest answer. A D&D party is four to six heroes. And each hero fills a square. An encounter space must have enough room for all the heroes to get involved. So, we need six squares minimum.

But then, we also need monsters. Small and medium-sized monsters take up the same space as heroes. One square apiece. But large monsters take up four squares. And this is where things get complicated. Because the number of monsters varies from encounter to encounter. The heroes could fight one small monster. They could fight 20 large monsters. That means the monsters could take up between one square and eighty squares. And that’s a lot of swing.

Realistically though, a combat encounter is going to include one to six monsters. And when monsters are big, there are usually fewer of them. So, it’d be reasonable to say the monsters need between one square and sixteen squares. Or maybe a total of 20 squares.

So, if we have 30 squares on the battlefield – a space that is five squares by six squares or 25 feet by 30 feet – we have enough space for the good guys and bad guys to stand around. And, for perspective, you could fit one-and-a-half of those in a small to medium suburban home. Basically, if you live in a two or three bedroom, one-and-a-half-bathroom house, you live in the minimum space needed for a D&D encounter.

But this isn’t a Final Fantasy game. We need more space on our battlefield. The heroes and the baddies don’t just stand on either side of the battlefield exchanging hits. Combats like that are boring. Seriously f$&%ing boring. People need to be able to move around.

In D&D, most creatures can move 30 feet in a single move. That’s six squares. Now, you MIGHT be tempted to add six squares of movement in each direction for every creature. That would mean you’d need 6 squares for PCs to stand in, up 20 squares for the monsters, and 144 squares for each participant or 1,728 squares, which is a total 1,754 squares. That would require a space approximately 42 squares on a side or 210 feet square. That’s pretty f$&%ing huge for an “AVERAGE” battle.

Obviously, something is wrong with our assumptions. Each creature doesn’t need 144 squares of movement. If you think about how a battle plays out, you have the heroes on one side and the baddies on the other side. And in the middle, there is a big space where the battle plays out. And THAT space needs to supply enough room for people to move around in. Everyone isn’t going to be moving at once.

Beyond that, there’s an idea called degrees of freedom. If the PCs, for example, start on the south edge of the battlefield, they probably aren’t going to be moving south. So, they need enough space to move north.

So, realistically, we really only need about 6 squares between the forces. We COULD get away with a battlefield that is 6 squares by 6 squares with extra space along the edges for the heroes and the baddies. Right?

And if we figure that the heroes and the baddies will each fill a “row” at the start of a battle, that really means we could get away with a space that is roughly 8 squares by 6 squares. That would be the smallest space for an encounter.

Except that’s a little bit anemic. And it’s anemic for two reasons. First of all, if everyone can cross the space in one move – basically anyone can get pretty much anywhere in one move – then movement isn’t interesting. See, every hero gets to move AND take an action. That’s the default. So if everything is within one move, there is never a situation where the distance forces any sort of tough choice BY ITSELF (we’ll come back to the reason for the emphasis).

Furthermore, there are some classes and creatures that move faster than 30 feet. If that is going to mean anything, there has to be a possibility, even in small encounters, that 30 feet isn’t enough. That way, the fast moving monk, the wizard that cast expeditious retreat, the orc with the aggressive trait, and the fast-moving dire tire all sometimes get a benefit from that enhanced speed.

Now, we don’t need MUCH more space. 35 feet is the same as 55 feet to a creature whose speed is 30 feet. A couple of extra squares is all it takes.

Beyond that, the other reason to overestimate the space is because most creatures are BIGGER than one square. We just don’t realize it because we aren’t thinking about size the right way. In order to move past an enemy, you don’t just need to exclude the space they are in, you also need to exclude the spaces immediately around them. Why? Because of opportunity attacks. A small or medium creature takes up one square of space, but because they have a zone of control that extends into the adjacent spaces, each enemy is nine squares large for the purpose of blocking enemy movement. Now, that’s a big tactical thing. Heroes and enemies will use their zones of control to their advantage. Zones of control is how they control choke points, how they range themselves to defend one another, and so on. And in order for zones of control to be useful BUT avoidable, the space needs to be slightly bigger than it needs to be. If that makes sense.

All told, we can conclude that a small encounter needs about 8 squares by 8 squares. That’s the MINIMUM. That’s the absolute smallest space we can start building an interesting combat encounter in. Especially once we consider that we’re going to fill it in with terrain like pits and rubble and water and mud and even walls. So, 40 feet by 40 feet is the smallest or a total of 64 squares is the smallest we’ll make an encounter.

Now, let’s talk about the BIGGEST possible encounter. The thing is, there’s a point where an encounter is just TOO BIG. And there are two considerations. First, there’s movement. If it takes multiple rounds just to engage with the enemy, then the combat is going to start off pretty boring. So, let’s figure this out. First, let’s imagine the scenario wherein two forces start on opposite sides of the battlefield and move to engage. We’ll say they have to be making useful actions in round two or else the combat is boring. So, that means each hero or baddie can spend the first round just moving. Creatures that dash can move 60 feet in a round, on average, or 12 squares. So, with two forces moving toward each other, that’s 24 squares of distance they can close in one round. In the next round, one side will then take a move action and attack. So, that’s another 6 squares. So, we could argue that a space 30 squares wide is the maximum amount of space, or 150 feet.

But the problem is that scenario CAN’T happen in D&D. You cannot have two forces in a dungeon, 150 feet apart, roll initiative and charge each other.

Why? Because they can’t SEE each other. Ever.

Most of the dungeon is dark.

Now, creatures that can see in the dark can see about 60 feet. That’s the general limit on darkvision, blindsight, tremorsense, and other weird senses. Yes, it does vary and there are a few very rare creatures that push BEYOND that limit. But most creatures can’t see more than 60 feet in the dark.

The heroes are in even worse shape. There is probably always going to be that one hero that can see in the dark and that hero will have the same 60-foot limit. But if the party doesn’t have darkvision, they will probably have a limit closer to 40 feet. That’s the maximum radius of a torch or a light spell. Lanterns can increase that, sure. A bullseye lantern is great. That pushes the limit to 120 feet. But simply put, you will never have two forces that roll initiative when they are 150 feet away.

Ultimately, the upper limit of the distance BETWEEN forces is 12 squares or 60 feet. Adding in the space for creatures to occupy at the start of the fight and allowing for the visibility SHOULD effect the battle with pools of darkness beyond the edges of light sources, the maximum size for an encounter is probably 15 squares by 15 squares or 75 feet by 75 feet. And THAT is pretty big. In a case like that, the encounter will probably start closer to the middle of the room, but there is a space of fog of war around the edges that creatures might be able to take advantage of.

This also suggests a neat optional item we can hide in our dungeon. A better light source. Because now we’re going to be forcing the GM to consider the light source. And that means we’re also probably going to have to add a sidebar about how to easily keep track of light. Games like Metroid and Dark Souls have usually include some optional items that don’t unlock areas but they do make things easier in some places. For example, Dark Souls has the Rusted Iron Ring that makes it easier to fight in waist-deep water. Super Metroid has the Charge Beam which is not required to beat the game but does make a lot of stuff easier. And it has the X-Ray Scope which makes it easier to spot secrets.

The point is, for the most part, we’ve narrowed in on the idea that an encounter space is very constrained. We don’t want to go much below about 8 squares by 8 squares and it can’t really go above 15 squares by 15.

And we can do a little better than this. We can come up with some vague classifications for encounter spaces. A small space is about 8 squares by 8 squares or 64 total squares if its misshapen. A medium space is 10 squares by 10 squares or 100 total squares. A large space is 12 squares by 12 squares or 144 total squares. And a huge space is 14 squares by 14 squares or 196 squares.

Lower level areas will favor smaller spaces because there will be fewer creatures and smaller creatures. Higher level areas will involve larger spaces because there will be more creatures and larger creatures. And once we push past a medium space, lighting is going to be an issue. But we’ve also fixated on lighting as something we can offer advancements for. In fact, I can think of three ways to improve lighting overall. The first is just shedding light over a larger area. The second is a light source that moves by itself and doesn’t require a hand to carry it. The third is a light that sheds light only for a specific creature, like a rogue that doesn’t have darkvision. We just file those various ideas away for now. We’ll use some of them later.

Next week, we’ll see if we can’t actually map out a day or two or three.

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21 thoughts on “Megadungeon Monday: Mapsturbation and the Size of Encounters

  1. This post reminds me of why I love grids vs hexes. Hexes are (in my opinion) prettier to look at, but are a pain to plan and play with.

    How do you feel about hex, Angry?

  2. Hmm… I may be missing a point here (probably am) but… are ALL areas expected to be dark? No glowing moss, phosphorescent crystals, lava streams or more mundane and less goofy — lit torches or sconces? Because if a room can be self-lit — you have missile weapons (and spells) to consider which have their own longer ranges, changing the engagement dynamic and thereby the potential space of your rooms.

    • If the rooms are lit, the upper-limit constraints for combat don’t matter; you can make a combat space of any size you want. Whether Angry plans to make all the rooms dark or not, the rooms that ARE dark are the ones whose constraints are important.

      • But the sizes do matter if you are going to make a map that works — aka fits in a ‘real space’ rather than just an interest-flow chart (I rarely ever get passed the flow-chart phase, but this is a different challenge he’s working on).

        • If we’re looking for an upper limit on the size of encounter spaces, which I think is what we’re talking about, then darkness is actually a tool we can use to provide extra constraints that narrow our range of possible sizes.
          If you don’t want to use the darkness mechanic as a size constraint, but still feel like you want an “upper limit” to aid in planning, I would suggest falling back on the idea that characters should be doing something more purposeful than moving by the second round of combat. Using movement speed and, as you mentioned above, weapon and spell ranges, you can figure out a maximum size beyond which encounters are too boring. Angry has pretty much done this above, minus the range calculations.

          Still, I think the whole point of the darkness is to purposefully shrink the maximum encounter size, giving you a smaller range of sizes to choose from and therefore making it easier to map a dungeon of this scale.

      • Even in a dark room, the constraints aren’t that constricting. Note that Angry says that the party is almost certainly carrying a light source. So if the monsters have darkvision, they don’t need light sources, so whenever they see a glowing light, they know there are enemies near. If those monsters have good ranged weapons like longbows (or fireballs), then the combat can certainly start well beyond 60 feet away.

        This still means the combat is likely to happen in a smaller area than a hectare, if only because the monsters might, instead of immediately attacking, decide to scurry to cover and wait to ambush the party when they get closer, but having giant dark rooms is still meaningful in that sense, especially if later events cause the room to become lit (open the lava dam and get the magma stream flowing again), and possibly re-populated with different monsters.

        • As both Angry and Robot Phil Collins mentioned, though, having a combat start at more than a 60-foot distance means that the fight will probably be boring, especially if the enemies are focusing on making ranged attacks. Either the front-liners have to spend 2 rounds rushing in, which means they aren’t getting to use their cool fighting abilities, or the players take the same tactic as their enemies and both sides just sit taking potshots.

          Also, that kind of ambush – from a bunch of creatures in the dark against a party who are lit up – is the kind of thing that causes Combat Swooshes:

          At your own table you can choose not to call for an initiative roll or reveal the enemies’ presence, but by the book, the enemies’ locations would be revealed (despite the players not being able to see them) and initiative would begin.

          • Way late to the party…but isn’t the issue of “boring” mitigated by the fact that move-only rounds are not only much quicker than “action” rounds, but also that they offer some of the long-range combatants an opportunity to shine as well as providing a bit of an opportunity for tactical stratergery?

  3. I’m really glad you like to do the math on these sorts of issues. You’d think it’d be something discussed in a Dungeon Master’s Guide…

  4. Yay maps! Ever since Ptolemys Geopgraphy we’ve been trying to figure out how to represent physical spaces on a flat plane, and there’s no real solution because anything goes (HE left it to future generations to actually figure out how to draw his map). My own combat maps are Cartesian for instance, to enable a PC who skypes in from cyberspace to follow along with what I’m drawing on a whiteboard for the physical players. And though PCs don’t need many maps out of combat, I find giving them a nice 3-d orthographic regional map – showing visible landmarks in the area or on the horizon – really helps make sure the PCs are “seeing” the area like I need them too. It imparts a sense of place, and is great at starting the next round of “ok, which spot are we heading to first”. Half of the time my maps aren’t so much about where I want the PCs to go, as what I want them to see or even feel (insignificant, lost, awed etc). My weakness has always been the very fine-detail specifics, exactly what your explaining now. Your system of gradually increasing the “resolution” of your map is super fascinating, and quite brilliant! I look forward to seeing it develop further and further, and hopefully wrapping my head around the process enough to give it a try myself!

    • Yeah… (I’m feeling unusually contrary on this one — I guess it is because I find the notion intriguing and want to understand it) What about ambushes? What about trying to sneak by an “encounter”? Maybe since we are at the heavily meta stage this is a good and vague enough place to start. After all you have to start somewhere right?

      • You may want some rather large set piece encounter spaces for boss fights or interactive encounters. Not all of those are going to be at the end of the road…

        Also, all rules are made to be broken, and having a huge open field vs. opponents with long bows and druid zone control powers is its own type of challenge. (I’m going to run across this 30′ gap in cover while taking the defense action, so that Bob can run 60′ to that cover, and Carol can move and shoot without taking return fire.)

    • Isn’t it generally always possible to draw a line form the PCs to the enemies? And then just assume the middle is the centre? And aren’t the exceptions significantly exceptional that we can just go with the general rule and cross that bridge when we get to it on a per-encounter basis?

      I’m supposing you might be suggesting situations where one force is divided or the room is sort of triangular, with the PCs and enemies on one side and an objective or point of interest on the other side, but I do think these are exceptions to the general rule (general in the sense of what typical happens during the game).

      • The specific reference was to the encounter space being divided that way, with the PCs at the back of it on one side, and the mobs at the back on the other side, and not having interesting features start behind (or, as you mentioned, beside) the two groups. Here’s a brief list of situations where ‘the encounter’ might take up more space than just the area around the combat: Additional rooms full of adds, larger areas with more terrain features, running battles involving a non-combat objective with both parties moving in one direction, highly mobile battles involving open spaces and cover, ambushes where the party starts in the middle of a group, large set piece boss battles where there are objectives in various parts of the room (Think golem types and healing sources), stealth encounters where the party can ambush the mobs by approaching from different directions, environmental rooms that force mobility (the lava is creeping this way at 4 tiles per round), extra large spaces to allow highly mobile characters and monsters to shine (wood elf monks and archers), a large room with combat starting against one wall, giving the PCs the tactical option to back up into a defensible position, any time you want to have a combat where the PCs don’t have the option of stepping back outside the door and leaving the two tanks to hold it while the elf shoots over their heads.
        To be clear none of this is a problem with starting the discussion with ‘generally encounter spaces are going to be this big’, but there’s a large number of exceptions to that rule, and you don’t want to wall yourself in. In reality, I suspect the problem will be completely solved by the need to leave breathing rooms between encounters, so you’ll be able to suck up 2 encounters and the room between in order to make a single large space.

    • This is a worthwhile question and one I should have addressed. Because you’re right, it does SEEM like a really big stupid thing to assume. But it doesn’t have to be that way. I’ll respond to this question in next week’s megadungeon article, okay? But fear not. I am NOT building Final Fantasy style combats with all the goodies on one side or all the baddies on the other. Trust me. You’ll have your answer.

  5. Pretty sure I recognise that third alternate light source from a previous article on Darkvision.
    I believe you compared it to Draco’s Hand of Glory. 🙂

    • It’s actually older than Harry Potter. It’s a bit of European folklore. There’s a couple of versions. Basically, if you take the hand of a criminal who was hanged and use it as a candelabra for a candle made out of the criminal’s fat (it has to be the same criminal), you got a Hand of Glory. In some versions of the story, the candle would only shed light for the holder. In others, if you strongly presented the candle at anyone, they would be immobilized until it was taken away. Either way, it was – according to legend – a favorite of burglars. Other bits of the legend suggest the candle can only be extinguished with milk and that it can’t be carried across a threshold that has been treated with bile from a black cat and the blood of an owl. I THINK you also needed something from a hen. Probably yellow bile.

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