D&D: Five Different Shapes For Your Custom World
The other ‘most important step’ in making a world is hard to draw on a map – but it has huge implications, if you get really weird about it.
If you’re going to make your own homebrewed world, I would encourage you to get real weird about it. That’s half of the fun. But, only if it’s fun for you – just as a general caveat, all you really need to do to get started with your own world is figure out a single place where your game will start. It could be a town, a stretch of wilderness, or even just a single dungeon. You really don’t need much.
But. If you are the kind of weirdo who wants to know about plate tectonics and seasonal cycles; if you think it’s fun to picture the Fourth Age of High Magic and figure out that the Thaumatic Empire of the Elyssian Dynasty ascended beyond the mantle of the world, leaving behind only strange ruins that are only half-understood and almost entirely forgotten except by the last Scions of the Ash-Strewn House of Embers, then you’re probably going to love figuring out what shape your world is. Assuming you don’t already know.
Sphere

When you’re building a world, one thing to keep in mind is that you only have so much weirdness before your players will not be able to get their heads around what you’re trying to do. The same goes for you, the DM, who can only handle so much stuff before you lose track of which age the campaign is actually taking place in.
So picking a sphere for a world is both morally good and easy to do because you (and everyone else at your table) already know what that’s like.
Torus

If you have a more refined palate, though; if you’re the sort of person who enjoys the worldbuilding equivalent of ripe cheese or can taste the difference between different bottles of port or whatever, then you might consider the torus as a shape.
A toroidal world isn’t unheard of. In fact, D&D has an example of this – the city of Sigil is a whole world that exists as a torus. Though I think it’s on the inside of the torus instead of the outside of it. That’s something to think about for most of these shapes; sometimes your world is on the inside of the planet, like some kind of hollow world or whatever. Usually that’s a cool place for dinosaurs. But regardless, a torus is a closed ring/donut type shape where the world loops back on itself. You can really go hog wild from there.
Cube

I feel like having your world exist on a cubic world isn’t as strange as you might think. After all, everyone knows Minecraft by now. Not that everything necessarily has to be all squares, from that point forward. But if your world is a cube think about what that says for the edges/corners of the world. On the ground, it might not even matter all that much – how round does the world look from your window? (And if you’re on the Artemis II and reading this, fine, well played, you have me there.)
Plus a cube world has the added benefit of not having to do complicated math to figure out how you can move diagonally on a grid without it taking extra space. So sort of by default, every world in D&D 5.5E is on a cube, even if the lore says otherwise. You can’t argue with math.
Localized Region Amid Infinite Chaos

What if your world is a cradle of realspace in the midst of an effervescent, ever-shifting chaos/wild primordial energy? Sure, this could also describe where your whole universe is, but sometimes the world is just a plane that stretches out in each direction until it starts to run into the wild-spaces. If you know 40K or a game like Exalted, you know well what this shape is like, and how much fun you can have with it. Running the Wyld is one of the best things about Exalted, for me, for instance.
Disc

Finally, the humble disc. You could have a whole series about a fantasy adventure that takes place on a disc-shaped world. It doesn’t even have to be a round disc – you could have a floppy-disc shaped world too. It begs two questions: what does the world rest upon (elephants and turtles? something different?) – and what happens if someone decides to put the world disc into some kind of omniversal drive?
What shape is your world?