You mean that it loops around on one specific angle of the torus?
[1] This facsimile operated in part by synAC.Right, that's what I meant.
Okay then. Might be better if I new how to have a raytracer so I could model it, but... the area under and near under the sun's orbit would have a standard day-night cycle. The area opposite the outside of the sun's orbit would be in constant night, possibly getting to twilight as the sun rises above the torus. The outside sides would be the same as that. The area inside... bleh... there must be a model somewhere
[1] This facsimile operated in part by synAC.That'd actually be easy to model with POV-Ray. Poke me later in the afternoon, 'k?
EDIT: The ratio between the planet's rotation speed and the sun's orbit speed would make a big difference. What ratio are you thinking?
edited 1st Dec '10 10:02:09 AM by Tangent128
Do you highlight everything looking for secret messages?Um, a radius isn't an object, it's just a measurement. The sun rotates around the ring, yes?
[1] This facsimile operated in part by synAC.
Like I've pointed out, it's orbit would take through the world's rotational axis, so that the inside portion would be lit all at the same time.
EDIT: and besides, I was using terminology from 3DSmax. I've been using it a lot at work lately.
edited 1st Dec '10 11:49:34 AM by Vorthon
"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. ClarkeCelestial Mechanics 101: objects rotate around the center of gravity of other objects. If the size of the object varies around that center, the pull of gravity likewise varies, which results in an irregular orbit. That's why typical objects are spherical, so that their gravity is regular and orbits are regular.
Upshot is, your sun would orbit around the center of the torus, not the surface, unless you use some serious hand waving.
Of course, in fantasy you don't need to worry about reality. Maybe the sun is a flaming chariot on a Moebius strip that floats around the world. That makes more sense than quantum physics.
Under World. It rocks!

I admit I suffer from ADCD.
Okay, now that I've got that out of the way, I was wondering how the day/night cycle would work for a world like this:
The world is a large torus, and it spins. The sun is smaller than the central hole of the torus and it orbits the small radius of the torus, so that it passes through the hole. What kind of day/night cycle would this produce?
EDIT: I should probably mention this is for a fantasy setting.
edited 1st Dec '10 8:54:17 AM by Vorthon
"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke