Is your world round? Do the PCs know it.

[Psion]

And interesting prospect of a Torus is gravity. If gravity is stronger than the "centrifugal force" (that is, the effect created by inertia and rotation) on the Torus, then you can only live on the Outside. In the Inside, you would plummet toward the hollow core. If the gravity is weaker, then it's the reverse -- you can only live on the Inside, on the Outside you would be yanked in outer space for all eternity.

FYI, a ring is not like a hollow sphere when it comes to gravity. There would still be stark differences and obvious contrasts between the surface conditions on it and a normal spherical world, but it doesn't have a uniform-zero-g zone in the middle like a sphere would.

 

[d4]

the last campaign world i designed was flat, for a fairly trivial reason.

i hate having to deal with the distortion you get trying to project a spherical surface onto a flat map... with a flat world, the map has a one-to-one correspondence to the world, and you don't have to worry about distortion.

edit: a torus has the same property.

one way to light Torusworld would be to have the sun do a figure-eight around the sides of the world -- around the outside, then through the center hole, then around the other side, back through the hole, etc. have the sun gradually precess around the torus so that all of the outside eventually gets some sun.

you end up with an interior that has a fairly normal day-night cycle, but on the outside, a particular region may only get sunlight once a week, month, year, or whatever (however long you determine it takes the sun to precess all the way around the torus). so the interior can be your relatively "normal" campaign area, with the outer "dark" areas being where monsters come from.

 

[Psion]

one way to light Torusworld would be to have the sun do a figure-eight around the sides of the world -- around the outside, then through the center hole, then around the other side, back through the hole, etc. have the sun gradually precess around the torus so that all of the outside eventually gets some sun.

you end up with an interior that has a fairly normal day-night cycle, but on the outside, a particular region may only get sunlight once a week, month, year, or whatever (however long you determine it takes the sun to precess all the way around the torus). so the interior can be your relatively "normal" campaign area, with the outer "dark" areas being where monsters come from.

Wierd.

My players must visit it as a stop along the River of Worlds...

 

[Gez]

the last campaign world i designed was flat, for a fairly trivial reason.

i hate having to deal with the distortion you get trying to project a spherical surface onto a flat map... with a flat world, the map has a one-to-one correspondence to the world, and you don't have to worry about distortion.

edit: a torus has the same property.

The same property as a sphere, or as a flatworld?
Because you do have distortion with a torus. Less than with a sphere, but you have a bit of distortion nonetheless. The inner circumference is shorter than the outer one, yet when you make a flat map of the torus, both are given the same size.

 

[orsal]

The same property as a sphere, or as a flatworld?
Because you do have distortion with a torus. Less than with a sphere, but you have a bit of distortion nonetheless. The inner circumference is shorter than the outer one, yet when you make a flat map of the torus, both are given the same size.

That's assuming that you are embedding the torus in Euclidean 3-space. I recommend thinking of it as a donut to get an intuitive feel for the topology (what is connected to what), not the geometry (distance measurements). For distances, take the unfolded torus (just a rectangular sheet of paper) as your map, to perfect scale, but use wrap-around if anyone travels off the edge of the map.

 

[orsal]

FYI, a ring is not like a hollow sphere when it comes to gravity. There would still be stark differences and obvious contrasts between the surface conditions on it and a normal spherical world, but it doesn't have a uniform-zero-g zone in the middle like a sphere would.

And if you want your fantasy worlds to confrom to modern physics, that's a serious issue. But you insist on your D&D agreeing with real-world physics, you have some issues much bigger than the structure of the gravity field.

 

[Psion]

And if you want your fantasy worlds to confrom to modern physics, that's a serious issue. But you insist on your D&D agreeing with real-world physics, you have some issues much bigger than the structure of the gravity field.

False dichotomy. It's not necessarily an all-or-nothing thing. Sure dragons can fly, but they have a waiver against the law of gravity.

 

[Gez]

Well, when you give up an odd shape to a world, it's interesting to look at possible consequences. Things like the long night on the Outside proposed by d4, or gravity variations, can be interesting.

Of course you'll use the magic wand to keep everything holding together, but if it's to set everything to exact Earth-like conformity, what's the purpose of having a donut- or banana-shaped world? Heck, what's the purpose of giving a shape to the world? A map of the continent, or a few continent, is all you need.

The world can be infinite and flat, or just big and round, or it can have the same shape as an cosmically-sized DNA chain -- but if it doesn't change anything, it doesn't matter deviating from the norm.

 

[Umbran]

The existence of a north pole and a south pole on the earth are due not to the shape of the earth itself (for, if we take a little license to pretend it's a perfect sphere there is no way to distinguish any point from any other), but rather from certain astronomical phenomena, most notably the motion of the sun around the earth.

You might want to double check that. Last time I checked, it was far more useful to consider that thge planet was going around the sun.

Technicall, our real-world north-south and the poles are results of the planet's spin. The poles are simply where the spin axis intersects the surface. If your torus spins, the residents would be likely to think similarly - North would be toward the positive spin end of the axis, south would be towards the negative end of the spin axis. East would then spinward, west would be antispinward.

The same phenomena determine east and west as directions but not as poles. I was thinking of doing something similar with all cardinal directions on my torus-world.

To my way of thinking, the cardinal directions of a world should not be set up in a way that is mathematically nifty just for the sake of niftiness. The populace of the planet will use coordinates because they are useful not because they are spiffy geometry. Sailors and farmers and armies care about the rising and setting of the sun, and the seasons. Higher mathematics aren't their forte.

 

[Umbran]

This torus-world talk has me wondering what the sky-view would look like. Would you plot such a thing in a normal universe with a sun that it revolves around, etc, or do something different?

Well, one obvious way to work with it is to make it a ringworld. Put the sun at the center of the torus. You now have a dayside and a nightside to work with - no need for underdark, when the "outside" of the torus is in perpetual darkness. You can get soem interesting seasonal light and dark by having the sun oscillate up and down along the axis of symmetry.

Or, you take the thing, spin it around it's axis of symmetry, set it orbiting around a sun. You tilt the thing significantly, so the inner surface of the torus also gets sunlight, and there's no permanent dark area. That tilt will also produce some impressive seasonal effects, and the regions that have seasonal 24-hour light and dark will also be large...