So I'm planning a D&D campaign to alternate with the game I play on weekends. I've talked over it a bit with the players, and it's going to be a campaign with an urban setting. And I mean urban, to the point of a medieval version of a city the size of New York.
(Oh, and one of the players is certainly going to read this. I don't care. It won't spoil the fun.)
I don't know for certain what kind of characters the players want to play, except that one of them wants to play a warforged monk. I suspect another would be more than happy to play a good-aligned cleric. A couple more are probably into power characters like paladins (which they wouldn't be able to hold alignment to) or fighters. Another would make a great rogue, but I don't think she's planning on attending in the future.
Now...back to the city. Having an entirely urban campaign changes a few things.
Random encounters
First, it means random encounters have to change significantly from the usual wild animals and monstrosities. More often than not, random encounters will involve thugs and pickpockets. In some districts, magical beasts might occasionally bust their way out of a magic shop. Turns out there are a couple pages in the DMG dedicated to this, but no matter.
:-)
After a few encounters with the players, word will get around, and low-level thugs aren't going to bother the players, though local gangs and syndicates might.
Classes
Second, some of the classes are going to need to be repurposed. Druids, rangers and barbarians aren't obvious choices, so they need to be made to fit, or done away with entirely.
I don't know how to deal with druids, short of removing them; There's not a lot of nature left in a megalopolis. Socially, druids would be community leaders, but it's not obvious how to change class features to suit.
Rangers are easy. There's an Urban Ranger variant in Masters of the Wild. Just switch a skill, some spells, a feat, and take an organization or culture as a favored enemy.
Barbarians are almost as easy. In a medieval fantasy setting, if you get an orphan, that orphan either dies or becomes a thief/rogue. But it takes a certain amount of brains to be a successful rogue. It's not a stretch to think that the kiddies with brains become rogues, and the kiddies with brawn become urban barbarians. The rogue kiddies would turn to theft and pickpocketing as a way to make a living, while the urban barbarians would form gangs and terrorize neighborhoods. While they're still kids, of course. (Hm. That gives me a great idea for heart-wrenching encounters and plots.)
Orphans (Don't know why I put so much thought into this...)
That brings up another wrinkle; Age of adulthood. In D&D, humans are listed as having reached adulthood at 15, half-orcs at 14, half-elfs and halflings at 20. That's fine, for humans, half-elfs and half-orcs; It's not hard to picture how at least some of them could survive to adulthood in kiddie gangs, though strength and age would definitely be major factors in survival and leadership.
Halflings are tougher, though; I don't see them surviving six months as a barbarian in that kind of environment. They'd have to either develop rogue abilities, sorcerer abilities or die, near as I can tell. At best, a few might discover talent as sorcerers; There are a few cantrips that would be help survival in either in a domineering role (acid splash, ray of frost, touch of fatigue), manipulative role (ghost sound, dancing lights), or even a productive role (prestidigitation, mage hand, mending). So there's not likely to be many orphaned halflings running around. However...Anyone ever think about how big a halfling child is? A ten-year-old halfling child would literally be tiny. But would he be physically and emotionally developed enough to do anything?
A twelve-year-old half-elf would be equivalent to a seven-year-old human. Could potentially develop some rogue skills, might get by as a junior barbarian.
A full elf isn't mature until 110 years old. I suspect that's more social and mental development, though; I can't imagine someone being as unproductive as a toddler for forty years. Let's say they're physically mature at 25. Presuming the same under-13 year old range for our orphans, they'll have only a slightly easier time of it than halflings; Mentally, they'll be behind, but they'll be somewhat stronger physically. So they're probably stuck at the junior barbarian level, unless they're extraordinarily apt and develop rogue or sorcerer skills.
Gnomes have the size problems of halflings, but an even longer time to maturity. If an orphan survives, I have to think they'll be an assistant or apprentice of a performer or tinkerer.
Dwarves don't become orphans.
Food
Fourth, there's the problem of how a city like that survives. Food has to come from somewhere, and waste has to go somewhere. New York has 8 million people. Let's do some numbers!
Figure three meals per day, for the entire population. The PHB gives three types of meals: Poor, common and good. Poor meals are said to consist of bread, a couple of vegetables, and water. Common meals replace one of the vegetables with a cheap meat stew, and add a little alcohol to the water. Good meals consist of bread, pastries, good meat, good vegetables, and alcohol.
Let's figure out how much food that is. Arms and Equipment Guide gives us easy numbers for bread. A loaf is 1/2 lb. Figure a loaf lasts one person a week, so we'll cut that to 1/10lb of bread per day. Figure 1lb per day per unit vegetable, 1/2lb per day per unit cheap stew, 1/2lb per day unit pastries, 1lb per day per unit good meat, 1/2lb per day per unit cheap alcohol, 1lb per day per unit good alcohol.
So a day of poor meals consists of 1/3 * ( 1/10lb bread + 2 * 1lb vegetable ), or 2.1 lbs of food per day.
A common meal consists of 1/3 * ( 1/10lb bread + 1 lb vegetable + 1/2lb stew + 1/2lb alcohol), or 2.1 lbs of food per day. (Convenient...)
A good meal consists of 1/3 * ( 1/10 lb bread + 1/2 lb pastries + 1lb meat + 1lb vegetable + 1lb alcohol ), or 3.1 lb of food per day.
At this point I need to figure out some demographics for the city. Figure 60% of the city eats poor meals, 39% of the city eats common meals, and 1% of the city eats good meals. So that's 4.8 million people eating poor meals, 3.12 million people eating common meals, and 80 thousand people eating good meals.
So what's the most obvious way to get food into the city? Well, by carts, of course. A long chain of carts that moves food into the city. So...How many carts? That still depends on how far the carts have to go. Some city topology needs to be determined, then.
Topology
So we've got 8 million people, right? Let's make the city out of building "blocks", then, and figure out what we can handle.
At a macro level, the city is a set of concentric rings, with the poorest district on the outside, the "common" district in the middle, and the richer folks taking up the center. The calculations were done assuming square lots, with alleyway and thoroughfare adjacent to each. Not the most efficient way, but it simplified calculations.
Poor lots hold eight people in a space 50 feet wide by 100 feet deep, with five feet of alleyway and 25 feet of thoroughfare adjacent. That leads to a population density of 43,518 people per square mile, and a total population area of 110 square miles.
"Common" lots hold four people in a space 100 feet by 100 feet, with the same road allocation as poor areas. That leads to a population density of 11,013 people per square mile, and a total population area of 283 square miles.
"Good" lots hold 16 people in a space 200 feet by 200 feet (but it's a taller building...), with 25 feet of alleyway and 50 feet of thoroughfare adjacent. Thad leads to a population density of 10,813 people per square feet, and a total population area of 7.4 square miles.
With the concentric ring layout, that means the rich circle has a radius of 4.8 miles, the "common" population extends the radius out to 30 miles, and the poor circle extends the radius out to 35 miles.
Now, the circle (and rings) are divided into 8 slices, and, in the center of each section of each ring, is the point where food gets distributed for that ring.
Food Distribution - Mundane
Now, food comes from outside the city along eight arteries that pass through each of these points. Food obviously doesn't need to travel all the way to the center of the city if it's going to be distributed at the edges. So how far does the food need to go, and how will it get there?
(The following calculations allow a 20% margin; With all the mules healthy, the city could handle a population surge of 20%. Or 20% of the mules could get sick.)
A mule can drag 3,450 lbs at a base speed of 20 ft, and we'll presume a mule can work 16 hours a day. That means a mule can can handle about 125,454 mile-lbs of food a day. The poor neighborhoods need about 26.3 million mile-lbs per day handled, the common neighborhoods need about 118 million mile-lbs per day handled, and the good neighborhoods need about 10.2 million mile-lbs per day handled. That works out to needing about 254 mules to service the poor neighborhoods, 1,130 mules to service the "common" neighborhoods, and 98 mules to service the good neighborhoods.
If you were standing on an artery between the city edge and the poor district's distribution center, mules headed to the local distribution point would be an average of 438 feet apart, and would go by every two minutes. If you were standing on an artery between the poor distribution center and the "common" distribution center, mules heading to the common distribution point would be an average of 673 feet apart, and would go by every three minutes. If you were standing on an artery between the "common" distribution center and the rich folk's distribution center, mules heading to feed the rich folks would average almost three miles apart, going by every hour and a quarter.
All my calculations can be found in
this Google Spreadsheet.
Food Distribution - Magical
Well, not just distribution; Create Food and Water could see major use in a city of this size. There would likely be folks who's only job is to contribute to feeding the city. I could use help on building NPCs for that purpose.
Waste
What goes in, must come out. One obvious solution to the waste problem is a massive sewer system underground--A real adventuring opportunity, for people of high fortitude.
:-) There are other uses for waste, though. Fertilizer (All that food has to come from somewhere...), fuel, components for building clay. It's gotta go somewhere. And there are likely some pretty nasty penalties for not taking care of it properly, no pun intended.
Other thoughts
It's 2:30AM, and I've got to go to work tomorrow. Any other thoughts and ideas?
(Oh, and it looks like Slashdot doesn't like my formatting. Tough cookies.)