By God I love a good random generator, and Spelljammer's Universe Builder is the ultimate in both scope and elegance. I'm going to create myself a little planetary system, just for the hell of it. Today I'll do the basics; tomorrow we'll see about fleshing things out.
1. System Type - Is our system your ordinary orbital one, or is it 'special' (a void, nested spheres, etc.)? The answer: standard. That's fine, this is our first effort after all.
2. Primary Type - Do we have a central sun/star, or do our planets orbit something weird and wonderful like a portal to the Negative Material Plane? Earth Body. The centre of this system is not a sun or star, but a body of elemental earth. Less weird than it could have been, but stranger than average. It's a massive cluster of asteriods surrounded by a huge, saturn-like ring of magma and fire which provides light and warmth for the entire system, and it is called Iburi.
3. Number of Planets - 6. Perfect - not too many, not too few.
4. Planet Types. Let's find out what's orbiting Iburi.
- First up is an Earth type, which we'll call Abashiri. It's a tiny flatworld - a disc floating in space a safe but slightly uncomfortable distance from Iburi.
- Second is Shiribeshi, another Earth type, considerably bigger than Abashiri, with an irregular shape; it takes the form of a gigantic U, with its inhabitants living on the outside edge. It is locked into a permanent ice age.
- Next is a Water planet, Rumoi. It is gargantuan, a monstrous oceanic sphere floating through space. It has a cluster of 13 asteroids in orbit around it, believed by its inhabitants to be the corpses of 13 dead gods.
- Fourth we have Utashinai, another Earth type and another giant to rival Rumoi in size. It is uncommonly hot, with a geography characterized by steaming jungles, parched deserts and vast sultry swamps. This is caused by massive levels of volcanic activity on its surface.
- Fifth is an Air planet, Muroran, another mighty body, composed entirely of swirling wind, clouds, and pure oxygen. It is vastly distant from the other four planets, but is known to have one, solitary moon.
- Finally, furthest from Iburi but itself a great source of light and heat, is Tomakomai, a great flat disc of flame. It is dominated by one great civilisation (perhaps beings of elemental fire?), and has 4 scorched moons orbiting it.