Shape
Source GM Core pg. 139
In a science-fantasy setting, the shape of your world need not be spherical as governed by the laws of physics. It could take on any shape you desire, and it might not be a planet at all!
Globe: Barring some catastrophe, worlds in our reality are roughly spherical due to the influence of gravity.
Hollow World: What if the landmasses and civilizations of a world existed on the inner surface of a hollow sphere? In such a world, the horizon would climb upwards, permitting creatures to see landmarks at extraordinary distances. A vast civilization might inhabit the interior of the world, lining the outer edge with solar panels for renewable power. Light might emanate from a sunlike orb in the world's center, from various other natural, technological, or magical sources, or not at all.
Irregular: What if your world is flat, a toroid, or shaped into a cylinder, cube, or other polyhedron? What if it's something even stranger? With such an unusual shape, you need to decide how gravity, atmosphere, and other details function. These types of irregular shapes can also include asteroids, colony ships, and space stations.
String: The world might be something entirely unique, like a stellar waterway akin to the River Betweena chain of stellar debris each a mini-world in its own right, or even a planetary ring detached from its maiden world and cast into the void.
Globe: Barring some catastrophe, worlds in our reality are roughly spherical due to the influence of gravity.
Hollow World: What if the landmasses and civilizations of a world existed on the inner surface of a hollow sphere? In such a world, the horizon would climb upwards, permitting creatures to see landmarks at extraordinary distances. A vast civilization might inhabit the interior of the world, lining the outer edge with solar panels for renewable power. Light might emanate from a sunlike orb in the world's center, from various other natural, technological, or magical sources, or not at all.
Irregular: What if your world is flat, a toroid, or shaped into a cylinder, cube, or other polyhedron? What if it's something even stranger? With such an unusual shape, you need to decide how gravity, atmosphere, and other details function. These types of irregular shapes can also include asteroids, colony ships, and space stations.
String: The world might be something entirely unique, like a stellar waterway akin to the River Betweena chain of stellar debris each a mini-world in its own right, or even a planetary ring detached from its maiden world and cast into the void.