Flat World design

[Gilladian]

Just as an exercise, because I've thought about it off and on for years, and have never quite wrapped my head around it, I would love some input on designing a "flat world" campaign setting.

Here are my ideas so far:
1) the world has an ocean in the center, a ring of mountains on the exterior, and rivers that run down from the mountains to the ocean.
2) There is no sun, and no moon(s). Day is simply "when the sky gets light" and Night is the opposite. There are times of "nightglow" but there is no actual moon (unless we invent a way to have one).
3) burrowing through (or climbing over) the mountains in the outer ring would only end up "coming out the other side"; the dwarves probably make a lot of money creating travel short-cuts this way.

Questions: Seasons? What's "up there?" and "down below"? What does the source of a river look like? Are there other planes? Is there an underdark? Is there a "backside" to the world disc? Is there really even a "disc" if there's a wraparound effect?

What would your answers be? What other questions need to be answered?

 

[aco175]

If there is no sun, then there would not be any evaporation of the ocean to make clouds and the rivers that come down from the mountains.. No rain makes a lot of arid places and no trees. There should be something that makes the evaporation and clouds come out from the middle of the world to the mountain ring.

There should also be some spinning of the world to give the world some mechanism for the clouds to travel to the mountains. This could also explain some seasonality.

 

[Umbran]

If there is no sun, then there would not be any evaporation of the ocean to make clouds and the rivers that come down from the mountains..

That's not quite correct. On our world, sunlight and air heat water, and that heat is what causes the water to evaporate. Any heat will do - it doesn't have to be direct sunlight. Direct sunlight means th water is heated more than if there were, say, clouds, but doesn't stop the process outright.

That being said, this setup is weird enough that appeals to our own planet's dynamics will fail - like how that disk is not gravitationally stable, and would normally collapse into a round world. The fact that tit doesn't means there's something else going on, which is perfectly acceptable for a fantasy world. It is just.. the wter cycle is probably the least of the world's problems in that regard.

There should also be some spinning of the world to give the world some mechanism for the clouds to travel to the mountains. This could also explain some seasonality.

Or, you just have a solid domed sky - water evaporates, reaches the lid, and it rolls down the sky to the edge of the world - like on the inside of a pot lid - where it flows into the rivers coming from the mountains. Sometimes it'll just drip off the lid, too, and it'll rain.

 

[Gilladian]

Oooh! I like the lid idea. That could also explain stars - the stars are tiny flaws in the crystal dome over the world; maybe there could even be mythology about "things from outside" attacking the world's dome/lid. I imagine a fairly shallow curve, like a lens, sitting on the top edge of the mountains. There could even be some sort of ridges directing the water to run down to specific places where the rivers are.

As far as the sun providing heat and evaporation, I could see maybe having a "hot spot" at the center of the sky. And it could slide around a bit to provide uneven warming to create currents.

I'm not at all worried about the answer being "magic" or "the gods" - it is a fantasy world after all! But I would like to have SOME form answers for big questions.

I don't see this world as being enormously large - maybe only a thousand miles across, or a couple thousand at most. That's big enough to have some good areas of diverse geography, like a desert and a large swamp, but small enough to be manageable in other ways.

I wonder if the "sun spot" could also vary in overall heat intensity over the course of a "year" - warmer in summer, cooler in winter obviously - that would help create seasons, right?

Or seasons could simply be a religious matter - perhaps each "season" is a particular god's purview, and they rotate power over the course of a year, allowing each season to occur as a signal that the particular god is dominant at that time.

This is fun!

 

[TwoSix]

I run Ravnica as a flat world, about 160 miles in diameter. The world is bounded by unbreakable walls. There's a "sun" that moves across the dome every 10 hours, followed by 10 hours of night (although the amount of magical light generated by the city means it's never really "dark").

There's water in caverns underneath most of the city, about a mile or two miles deep. At the bottom is more of the same unbreakable material as the walls.

Part of the campaign mystery is finding out what's underneath the "bottom". If/when they get there, they'll find a pristine, untouched realm divided into mountains, plains, islands, swamp, and forest. It's basically a reservoir of mana, which is recycled by the "sun" (which actually just collects ambient mana) every daily cycle.

 

[aco175]

Maybe some sort of mysterious island in the middle of the ocean where life originated or at least the original or favored race according to myth. This may be elves or dragons for all that matters. It may make some good dynamics.

 

[Gilladian]

I think 1000 miles as a radius. That's ample, especially if there is also a full underdark layer or layers. And I have always liked the idea of the feywild/shadowfell as the ONLY alternate planes - a chaotic, natural world filled with elemental and fey creatures, and a shadow world filled with ethereal and undead creatures. None of the 4e mythology, though.

What other major "world level" questions need answers?

 

[MarkB]

How do lycanthropes work if there's no moon? Is there a regular pattern of lighter and darker nights?

What do people say as directions in this world? Is there one particularly prominent (and maybe iron-rich and thus magnetic) mountain that people consider 'north'? Are there constellations or other visible features to provide guidance at night?

 

[Dannyalcatraz]

I think 1000 miles as a radius. That's ample, especially if there is also a full underdark layer or layers. And I have always liked the idea of the feywild/shadowfell as the ONLY alternate planes - a chaotic, natural world filled with elemental and fey creatures, and a shadow world filled with ethereal and undead creatures. None of the 4e mythology, though.

What other major "world level" questions need answers?

Are you going to run Tabaxi or Rakshasha as the main antagonists? You know...because they want to push everything over the edge?

 

[Eltab]

I recommend you read Niven's Ringworld novels (especially The Ringworld Engineers). He's already done some of the idea-work for you.