This looked pretty great and I immediately decided to inflict this on one of my groups. (And then a couple more because one is none!). However, as noted in this reddit post by ValdyrDrengr, the 4chan map is not quite right. The corrected version of the map was helpfully provided as a google sheets link.
The problem (at least at the time) was that a 5D dungeon wasn’t going to fit into my campaign.
Or was it?
And just like this, Tam got the worst idea in the history of ever. Let’s take the 5D dungeon … and make it planet sized.
For the sake of completeness: about 6-8 months into me running my planet-sized 5D dungeon, /r/dndBehindTheScreen received yet another thread (this one by mastering_dungeons). Unlike Drengr’s post, /u/mastering_dungeons did entertain the idea of the dungeon being a small planet.
I will talk about why exactly this is a bad idea in a follow-up post, though those of you who regularly play video games probably already know the answer.
Before we continue, a quick note: this post assumes you already know how the 5D dungeon works and that you’re reasonably familiar with the terminology. If you don’t, read Drengr’s or Mastering’s post — they made decent write-ups. But to give a quick recap of how travel in a 5D dungeon works:
- you can move along three axes (think up/down, left/right, forwards/backwards). That’s three dimensions.
- if you move along an axis in a straight line for long enough, you will end up where you started. That is the fourth dimension.
- each room has a teleport button, that will teleport you to a different room. This teleport is the fifth dimension. The key thing to note is that two rooms are actually the same room but in different dimensions.
- Just like a cube has 6 faces that are flat 2D squares, a tesseract has 8 faces that are 3D cubes (or, in our case, rooms). There are 10 tesseracts. Rooms within the same tesseract are accessible without teleportation (assuming passages are not blocked).
- Technically, each room is in two tesseracts at once. However, the rest of the writeup will pretend that this “same room” is actually two rooms connected with a teleport button.
The Archplane: a 5D World
As mentioned earlier, my goal is to have a 5D dungeon where each dungeon is a small planet. Ideally, the planets would be the size of a country. Their sizes can vary and in practice, but at the end of the day I decided to settle for something random, with radii of planets varying between 48 and 256 miles, with most common planet size being 96-128 miles, and with planets larger than that being exceedingly rare.
If you wonder why I went for these numbers: I wished to have planets that can be walked around in about 20 days to a month, given medium travel pace of 24 miles per day. I also wanted the numbers to be reasonably nice and round.
The Problem of Physics
Original implementations of 5D dungeon can get away with things like wonky physics, since they work on the scale of rooms. It doesn’t matter if gravity points in a random direction in every room when the room is (relatively) small, but if we want to scale up the rooms to the size we want, we want consistent physics. There are two options for that:
- The Halo Option2I am fully aware that Halo wasn’t a Dyson sphere.2 (a.k.a. Hollow World): the world is a Dyson sphere-like object, or a hollow cavern inside a rock. Gravity pulls players away from the center of the room.
- The Hello Option3I am also fully aware that nobody will catch that No Man’s Sky reference3 (a.k.a. a Planet): we turn the room inside out and get a proper planet. Gravity pulls players towards the surface of the planet.
Side note: from now on, I will be using the word “world” to refer to either hollow world or a planet in situation where the distinction is not necessary.
The travel between neighbours works similarly enough for both: as you travel from one neighbour to the other, the gravity will slowly decrease. Eventually, you will reach a bit of “zero G” space between the worlds. Once you pass the “zero G” area, the gravity will start becoming stronger again until you reach the surface.
This is a problem for hollow worlds, as things like water, loose rock, and other things that can obstruct the passage will be naturally attracted towards the zero-G space. Planets do not have this problem, since anything stuck in the zero-G space would fall down on the planet at the slightest perturbation.
But the planet option has a different problem: it’s much easier to justify a tunnel between two hollow neighbours than it is to justify anything that bridges the gap between two planets — not to mention that there is no guarantee that the gap between planets is filled with air (what is more — most people would probably expect you’d suffocate in the gap, since in real world, the atmosphere is pretty thin).
At the end the day, it turns out that we need to cheat a little and break the physics:
- For hollow worlds, we introduce a “region of fucked up space” that replaces the “zero-G” space. If a player were to walk from one world to its neighbour, the gravity would remain constant throughout the way, but would point in random direction in areas between the worlds. Gravity changes are continuous enough for people walking through the tunnel to not notice them.
- For planets, we introduce standard air pressure throughout the interplanetary space. We also magically wave in some lifts that connect neighbouring planets with infinitely strong ropes, or fall back to standard options of “yeah, airship, or dragon, or griffon, or wyvern”.
The Problem of Day and Night
Even with planets, the 5D world assumes that the planets are at a fixed position and — if you connected them with lifts — that they do not rotate. I don’t think I need to mention why the hollow worlds have this problem.
There are a few solutions to this: eternal day, eternal night, magical light that creates day/night cycle. The day/night cycle has two options: same time everywhere on all the worlds, and the option you should not even consider. Yes, you can have a lighthouse at the center of a hollow world or a light rotating around a planet, but that will give you timezones and a date line. Or, in other words, two things you really don’t want in your D&D game as they complicate time tracking a bit too much.
But at the end of the day, it doesn’t matter. All options are generally a cop-out, neither is very realistic. You will have to embrace the magic on this issue.
The Problem of Travel
Travel between worlds is crucial for experiencing the 5D dungeon the way it was intended. Thankfully, the solutions to this problem are dime a dozen:
- A system of tunnels
- Flying mounts
Whatever the travel method, the starting point for travel between two worlds should be located roughly around one of the six poles of the world (where ‘pole’ is a spot where any of the three axes going through the center of the planet intersects the surface).
The problem common to all of the methods is distance. This is something that you will probably want to handwave away very quickly, for two reasons. If the distance is too short, the planets will appear too close together. If the distances are too long, the travel time will take too long to be practically feasible, realistically speaking. However, you can handwave the distances away if players ask, with excuses like “there’s some weird optical fuckery going on with the air between the planets,” “something something magic,” or Tam’s favourite — “region of fucked up space.”
Besides the distance, however, each of the methods has their own challenges and benefits.
Tunnels and caverns
The obvious drawback of this option is that it can only connect hollow worlds. In addition, the tunnels would probably rather long (that is true even if you dig straight down, and it gets a lot worse if you don’t) and thus something that would be rather hard and time-consuming to dig.
But you don’t have to dig all the way through: you can pepper the way between two worlds with caverns, which can be natural or magical, small but common or vast (with little need for common).
Furthermore, travel through the tunnels can be augmented with lifts or rails (including lightning rails from Eberron).
While constructing a path through the rock and underground caverns would be something unreasonably expensive, you can stereotypically blame a lot of that on dwarves and their dinky dinky holes (and if you’re big on Tolkienisms, orcs and goblins as well) and most people will take it at face value.
This method generally only works for travel between planets. This option is perhaps the most obviously affected by the distance problem: if you rule that the mounts gain height reasonably slowly, the time to traverse the gap may quickly go over a full day if you want realistically practical inter-planetary distances. With this option, you will have to settle for either for very short inter-planetary distances, outright ignore any travel speed, or pretend that the animals don’t need to rest for the duration of the travel.
… or you could shake things up and introduce interplanetary winds, which make travel faster when travelling in one direction, but prevent the possibility of travel in the opposite direction.
Another thing about this option is that it strongly depends on the environment around your particular pole. If the environment around the crossing point is inhospitable to certain kind of creature, this option is off the table.
On the flip side, this option is easy mode for diversity, as candidates for flying mounts are reasonably plentiful. You have griffons for humans and elves, wyverns or manticores for orcs, you can import giant eagles from Lord of the Rings for some other race. Maybe you can even find a way to have dragons carry people over, though dragons usually aren’t the kind of creatures that would be willing to steep that low.
Another thing that probably has to be factored in with this option is carrying weight. It’s probably not too reasonable to expect flying mounts to be able to carry significantly more than their rider, but at the end of the day — that’s one more thing that you can either handwave away or deliberately use as a limitation.
This method shares a lot of problems with the flying mounts option, but there are a few notable differences. Namely, airships generally have significantly higher carrying capacity and are less affected by (in)hospitality of the environment (although wind remains a big problem). On the flip side, they are very expensive to construct: raising a flying mount probably costs far less gold.
Lifts are my preferred method of travel. They work the same way your average ski lift: there’s (at least) one rope going up, one rope going down, and a bunch of cabins that can be attached or de-attached at the station for loading and unloading.
But there’s a lot of things that need some hand-waving if you’re building a lift between two planets (hollow worlds can have any number of transfer stations dotted along the tunnels and caverns, which solves all the problems).
First is the problem of construction. The easy cop-out option to explain the lifts (if players ask) is to say that “they’ve always been there, nobody knows how they were made” or “gods made them.” But if you actually want to construct one from scratch, you will probably need a few airships or dragons or flying mounts to drag two ropes across the interplanetary gap — which is a pretty big endeavour.
Maintenance is somewhat easier, though. Once you have a lift, you can use that lift for maintenance or building any parallel lifts — no dragons or airships required. (That being said, it is entirely “legal” for a dragon to treat a lift as its “pet project” …)
The last challenge is powering the lift. The easiest go-to options for making the lift go round (beside “magic, deal with it”) is water wheels or windmills. However — remember the interplanetary winds mentioned earlier? We can put them to a good use here as well, by mounting sails on the lift cabins. While sails would add extra weight to the cabins, the interplanetary space has reduced gravity, which means the presence of the sails could generally outweigh the additional cost of extra weight. (That being said, I have done none of the maths to back that up!)
There is an additional curiosity when using the lift: about halfway through the world, the gravity will invert. This means that the cabins themselves should be designed either to rotate around as the direction of the gravity changes, or be symmetrical (so that ceiling and floor can fulfil either role).
Teleporting between worlds
Is the boring option as far as I’m concerned. Moving on.
The Problem of a Teleport Button
5D dungeon prescribes that each room should have a button that will teleport you to a different room, as that button is necessary for the travel in the 5th dimension.
This works when the rooms are room-sized, but when the “room” is a world the size of a country, the button solution becomes rather unpractical.
The easy solution is to change the button into a somewhat-common magical artifact that allows you to “switch” the worlds the same way you’d switch the room by pressing the button. This is how I ran the first iteration, but at the end of the day it turns out that we can do one better.
We can get rid of the teleport button entirely by combining planets and hollow worlds.
Let’s look at every pair of rooms on the original 5D dungeon and turn one into a planet and the other into a hollow world. Then, let’s put the hollow world inside of a planet and change rules of the game accordingly:
- Digging down (towards center from the planet or away from the center of a hollow world) will get you to the twin world, effectively doing the job of the teleport button
- Going up (skyward on planets, towards center of the hollow world) will get you to the neighbouring world.
This is pretty neat, as it allows for continuous travel in a straight line across all five dimensions. But some of you may have noticed a problem. Wouldn’t going up (towards the center) on hollow worlds mean you will eventually end on the other side of the same world?
I could try to explain what’s going on with words, but it’s easier to explain by dropping a dimension and showing you a picture.
If our planets were flat two-dimensional circles, we could exit the inner circle without ever crossing any lines by simply warping the paper the circles are drawn on, and then connect two points with a straight string.
In other words, we have effectively placed a wormhole (or a few) in the center of our hollow worlds (and also around our planets).
Describing the Worlds in the Sky
This is something where, for the sanity of you and your players (but especially you), you cheat. I have tried to figure out how neighbouring worlds would accurately appear from the surface of the world, but I haven’t watched enough Rick&Morty to figure that out myself.
Instead, I make up excuses. My favourite excuse is “even on a good day, you can’t see further than e.g. 24 miles 4The number is arbitrary, but ideally needs to be lower than radius for hollow worlds4. The rule is sometimes somewhat relaxed in the vicinity of places where neighbouring worlds are at their closest, because it’s good to see the world across the gap.
The second-best excuse is “there’s a lot of atmospheric lensing going on even in hollow world. This allows you to see (neighbouring world) on the horizon” … though save fancy sciency terms for out-of-character explanations. Especially if you’re playing with people who actually understand physics and optics.
Passages and Demographics
By looking at Drengr’s map, one might initially think that it’s logical for kingdoms to span across the neighbouring worlds while ignoring twin worlds. This, however, is not necessarily the case.
If the worlds are connected with lifts, then lifts are a massive choke-point. With distance being a potential problem for flying mounts and the price tag being the potential problem for airships, any invasion is incredibly difficult. On the other hand, if your “switch to twin” button is a common-ish magical artifact (which, if you want to run the planet-sized 5D dungeon to its fullest potential, it almost should be), then invading across this border becomes easy (since you can switch to twin at any time). As a result, a faction would likely control not every world in a tesseract, but both twins instead.
If your solution to the twin problem is nesting one twin inside the other (as outlined in the previous section), you get to have more control over travel between two twins by playing with how common the passages between the two twins are, and whether constructing new passages is easy or not.
But even if you limit the travel between twins, the borders between races, cultures, and kingdoms are most likely to exist not on the surface of a world, but between them.
If it’s always possible to travel between two neighbours or twins, navigation between planets will be trivial. This is perhaps not the best solution. Consider making some passages outright impossible, and some difficult. Fortunately, the list of things that can prevent, delay, or make passage inconvenient is not that short.
Lifts may be stopped for inspection and maintenance every now and then (although some races that are OSHA-averse may opt to perform maintenance without shutting down the lifts), or they may be stopped because they broke or because the wind that powers them is not blowing strong enough.
Bad weather — storms and high winds — are an equally good reason to shut down travel with lifts, mounts, and airships. Much of the same can be said for wildlife attacks — wild wyverens, manticores, griffons, or just angry geese — can be much more than an annoyance to fight off while traveling to a different world. Lifts, airships, and airship ports can all suffer damage from these factors, too (though to a lesser extent, this is also true for stables for flying mounts).
When traveling between two worlds through a tunnel, the parties are also in danger from cave-ins, ambushes (be it kobolds, goblins, orcs, bandits — whatever you want), tunnel floods (be it water or lava), or underground fauna.
Maybe a passage between two worlds is closed due to war or other natural (or supernatural) disaster, and maybe there was no passage between that specific pair of worlds to begin with … the options are endless.
Just Because You Can, It Doesn’t Mean You Should
Now that we’ve explored whether we can have a campaign set in super-sized world, it’s time to consider whether you actually want to run a campaign in a 5-dimensional world.
And the answer to that is … you probably don’t. It takes a lot of work to create and keep track of worlds, you will have to map out much more of the 5D dungeon than your players will see. You will have to face the fact that your players probably won’t see most of the things that you had to come up with. Since every world can be connected up to 7 other worlds (6 neighbors and a twin), you’re giving your party a lot of options to end up on a world that you didn’t plan for them to visit. There will be a lot of world maps to be made, and you will have to reasonably populate most of them.
If your answer to that is to soft-railroad your players into staying on a handful of the worlds, then you don’t need a 5D world. You can still have multiple smaller planets and allow players to travel between them in a similar fashion to what was outlined here. Less is sometimes truly more.
It also takes a rather specific kind of group to play such a thing with. If you’re playing with a bunch of The Banner Saga or Oregon Trail enthusiasts, you will probably be fine. If not … play something else.