When we sat down and began designing what a “planet” is in Imagine Nations, we had a few requirements:
A) It would fit within the cubic nature of the game versus the more expected “spherical” planet.
B) There would be a semblance of science to it as nature does some wondrous things. During the research phase, we ran into a series of articles ( Article 1 , Article 2, and Article 3) that hypothesized if a cubic planet could exist, and how this planet would look and act. It intrigued us, and we used the science as a base for our planets. This news post breaks down the science, the creative decisions, and how these all affect you both on and off planets.
On a simplistic level when breaking down these articles, there would need to be either a crazy phenomenon unforeseen in our understanding of physics that has allowed a planet-sized cube of dense rock to exist, or an artificial planet would need to have been created. Gravity would still act in a spherical manner which has caused nearly every cosmic body to become spherical (well almost (http://www.scientificamerican.com/article/earth-is-not-round)), which means that given enough time, these cubic planets would eventually become spheres.
Planets would be seen almost like 6 planets in one, with each face being entirely segmented from the others and wholly unique (including two faces acting as the poles). Due to their design, someone living on one of these faces could stand on the gigantic mountain ranges on the edges and see from one side clear to the other thousands of miles away (versus the limited range we can see due to Earth being rounded).
Generally, these planets would have a large ocean in the middle due to a unique “bowl-like” shape forming from the gravity. This would be surrounded by arable land, followed by desert, and then the huge mountain ranges.
Overall the articles above are fantastic reads to see what these planets could offer for you (if they really existed of course).
The Creative Decisions
When we approached these planets, there were certain aspects that needed to fit within a voxel game like ours. We wanted there to be as much variety (rather than cookie cutting the same ocean >> land >> desert >> mountain scenario), and therefore the planet generator will have many passes associated with it to ensure that every face is as unique as possible while still closely following the science of the planet as best as possible.
Gravity would not be able to work exactly how it would on a cubic planet (where the gravity is still spherical so walking further from the center of face would be pulling you awkwardly towards the center). There would also still be gravity affecting you at the top of the mountain ranges at the edges of each face.
In both of these scenarios, we have decided to have gravity only affect you in one direction based on the face you are on. We have also made it so the gravity is reduced to 0 roughly halfway up the mountains at the edge.
Why did we make these decisions? In terms of planet generation, we want the process of exploration to be alive not only on the first planet face you begin on, but every single planet you discover. If there is an expectation that they all will look the same, it will lose a lot of the luster.
In terms of gravity, it will be much easier to have one “world up” for each face in terms of storing all the block data. It will be very awkward for gravity to be pulling you at different angles based on where you are on the face. With gravity being 0 on the mountains, you can look at the space program in two stages.
The first stage flows similar to ours where we need to build rockets that get us out of our atmosphere (and all the difficulties associated with it). This may also be the first time spacesuits are created that could allow someone to begin visiting the other faces.
The second stage allows cultures to build shipyards and ports on the 0g portions of the mountains, thereby allowing nearly any style spaceship to be built without the constraints of gravity being taken into account. This also allows ground-based systems to support these shipyards without needing its own power sources, defense systems, etc.
Does the possibility of spherical planets exist within our game? Time will have to tell. Variety cannot hurt in the future, but we feel there will be able to plenty of variety with these cubic planets.