Planet Building (SkWN)

The following page describes how a planet and its characteristics is randomly generated, after System Creation has occured.

Planet Creation Procedure

1. Note the zone and lord (orbited object, either gas giant or star) for the planet.
2. Roll for the planet's Size and Gravity.
3. Roll twice for the planet's Planet Tags.
4. Roll for the Atmosphere, based on the Gravity of the planet.
5. Roll for the Temperature, modified based on the Zone of the planet.
6. Roll for the Biosphere, changing the rolled dice based on the Atmosphere and Temperature.
7. Roll to see if there is a notable Orbital Feature, modified by the planet's Gravity.
8. Roll to determine if the planet has any intelligent Inhabitants. If so, roll to determine the type of inhabitants, Development Level, and Population size. Optionally, roll Sovereignty and Government for the population.
9. Roll for the Resources present on the planet.
10. Write up a description of the planet. Create at least 1 NPC or creature that would be friendly to the party, 1 that would be hostile, 1 location, and 1 complication that could arise on the planet. Use the tags as guidance and inspiration!
11. If you prefer, roll up additional Optional Details to help flesh out the planet.

Planetary Data

Planetary information is organized as follows:

Inhabitant data are organized as follows:

Planet Generation Notes

Unless otherwise indicated, the minimum and maximum results of all rolls are 2 and 12, respectively. If a modified roll would be lower than 2 or higher than 12, treat that as a result of 2 or 12, respectively.

Size and Gravity

Roll 2d6 for the planet's size and gravity. Do not roll separately, read the result straight across.

Planet Tags

Generate two Planet Tags.

Only one planet in a system, the mainworld, requires Planet Tags. Once a system has a mainworld, the others should be built as supplemental locations. However, if you want to use Planet Tags for these worlds as well, feel free to do so.

Use planet tags as guidance for the random results you later receive. Resist the urge to attempt to override the results or reroll the Planet Tags if they conflict - instead, do your best to reconcile the results. However, if a result seems impossible or unfun, feel free to adjust the results after consulting with the other worldbuilders.

Alternatively, if you prefer, roll Planet Tags after rolling for Inhabitants (below).

Atmosphere

Roll 2d6 for the type of atmosphere on the planet, using the column corresponding to the Gravity of the planet.

Temperature

Roll 2d6 for the general temperature of the planet. If the planet is in the Inner Cauldron zone, add +3. If it is in the Outer Reaches, add -3. These modifiers are doubled if the planet's atmosphere is Airless.

Biosphere

Roll 2d6 for the Biosphere of the planet. If Atmosphere is "Breathable" and temperature is "Variable" or "Temperate", roll 3d4 instead of 2d6. If Atmosphere is "Airless", or temperature is "Frozen" or "Burning", roll 1d3+1 instead of 2d6.

Orbital Feature

Roll a 2d6 to see if the planet has a notable orbital feature. Modify the roll by +1/-1 for High/Low Gravity.

For Moon (Resource) and Asteroid (Resource) results, when generating Resources for the planet, generate 1 Mineral Resource for the orbital feature, with a -5 penalty to the Abundance roll. Note the Resource and the abundance with the Orbital Feature.

Inhabitants

Inhabitable planets are inhabited by an intelligent species on a roll of 9+ on 2d6. Uninhabitable plants are inhabited on an 11+. If the planet is the mainworld of the system, it is inhabited on a 7+ instead (regardless of its nominal habitability.)

For the purpose of this section, an uninhabitable planet is any planet with an Atmosphere besides "Breathable", "Thick", or "Thin", or has a Climate of Frozen or Burning.

Type of Inhabitants

If another world in the system is already inhabited, this world will only have different inhabitants on a 10+ on a 2d6. Otherwise, roll a 2d6 to determine which species inhabits this planet:

Entries with "†" should be rerolled for uninhabitable planets.

If the species is Human, decide whether or not the humans are Imperial colonists or other settlers (arriving in the last 1,000 years and knowing of the Imperium), or lost civilizations (unaware of the Imperium and perhaps settled in the Age of Strife or Dark Age of Technology.) For "lore-accurate" results, roll a 1d4: on a 1, they are Imperial Humans; otherwise they are a lost civilization.

Development Level

Roll 2d6 to see what level of development the inhabitants are at. Entries with "†" should be rerolled for uninhabitable planets.

Population

Roll 2d6 for the order of magnitude of the population, then multiply the order of magnitude by 1d10.

If desired, the 2d6 population magnitude roll can be used unmodified. However, for a "lore-accurate" population magnitude, modify the roll with the following modifiers:

Human (Extreme Worlds) refers to human inhabitants on any world where the atmosphere is not Breathable, Thin, or Thick, or the Temperature is not Variable or Temperate.

Sovereignty (Optional)

Optionally, multiple independent polities can be generated for Humans and Xenos (Minor). However, roll on the following table for Sovereignty instead of the version found in that post:

For explanations and the number of polities to generate, see (link placeholder.) If desired, additional polities can be of a different species, but should be of the same or equivalent development level.

Government (Optional)

Optionally, for Humans and Xenos (Minor) roll to determine the government, a combination of regime and administration:

For Kroot and Eldar Exodites (Primitive Clans), roll only for Administration. Kroot and Eldar Primitive Clans are always Tribal; Kroot Colonies are always Military.

Orks always have the government "Hooliganism." Rak'Gol always have the government "Despoiling Horde."

For descriptions, see (link placeholder.)

Resources

Generate the number of resource deposits on the planet, their type, and their Abundance. Note each deposit as a combination of type and abundance. For example, "Radioactives 27", or "Curative 55".

The number of Mineral Resource and Additional Resource deposits depends on a planet's size:

For each Mineral Resource, generate the type:

If you are worldbuilding collaboratively, do not roll to see which Additional Resources are found, just the number of deposits. Otherwise, roll to determine the type of Additional Resources:

For Organic Compounds, roll to determine which type:

Resource Abundance

Roll 1d100 for each Resource's Abundance.

Depending on the polities on a planet (if any), a certain number of resource deposits will be capped, representing the local population already taking them and using them to build their society. Cap the Resource's Abundance at the Max Deposit, according to the Development Level of the polity or Major Polities on the planet, for up to the No. of Resources. Depending on the Species and Population, the No. of Resources capped and the Max Deposit may be adjusted further.

Optional Details

Territories

Territories are specific areas of the planet, with striking landscapes, unique flora, or major landmarks. They may be remnants of planetary formation, host unique species, bear the marks of some ancient race, or hide the resources of the planet from orbital observation. Regardless, they are important and they have defined boundaries. Most of the planet will be made up of "typical" terrain for a planet of its type; Territories are those notable enough to receive a label on a map. Examples of territories from Earth include the Himalayan Mountains, the Sahara Desert, the Black Forest prior to human arrival, the Great Lakes, or the Nile swamp floodplain. Examples of territories outside Earth include Cydonia on Mars.

Uninhabitable planets have no Territories or one Territory, depending on what would be logical for them. Otherwise, the number of territories is dependent on planet size. Small planets have 1d3 Territories, large planets have 1d6 territories, and Vast planets have 1d10 territories. Inhabitable worlds with ecosystems have +1 territory.

Territories can be described in any way you want. If the planet has Tags that indicate certain physical characteristics, they should inform the Territories created for the planet.

If you want inspiration for the type of territory, roll on the following table:

Territories should have some aspect to them that makes navigating them different or more difficult than the rest of the planet. This can be the pure harshness of the terrain, but can also be for other reasons. A swampy wasteland could be full of mud and impede any ground movement, or it could be a toxic cauldron of diseases and plagues. A forest might be composed not of trees or planets, but some more exotic organisms or materials, like chitinous limbs or sighing flesh. Plains might be riddled with a karst landscape. A wasteland might bear no relief at all, and simply be an unrelenting zone of death. Territories could feature extreme landscapes, unique species, or be placed in an unusual location.

Landmarks

A landmark is a major, singular feature of the planet, unlike the regions that are Territories. Landmarks, depending on what they are, can assist with navigation, make travel easier or harder, expose valuable resources, or present a physical challenge to explorers. These are features that could appear on any planet, so it generally does not include any city or megastructure currently used by the inhabitants.

If desired, each Territory can have one or more landmarks. Landmarks, like Territories, should be guided by the Planet Tags. If you need inspiration for a Landmark, roll on the table below:

Write out the landmark with its territory, as "Territory (Landmark)."

Emblematic Beast

If there is a biosphere, feel free to roll a random signature animal found on the planet. Roll their Archetype and then their Nature.

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