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Mapcraft - Fantasy map designer

WorldGen - SciFi universe generator

Mapcraft Web - Web based fantasy map designer

All code for the project is released under the GPL, and is copyright Samuel Penn.

The text on this wiki is dual licensed CC-BY-SA and GPL.

You can contact the author at


Planetary Classification List

My latest version of this list is at

The aim of the WorldGen system is to generate random worlds which are diverse, interesting and also vaguely sensible. To aid in this, a broad range of planet types have been defined. This list is based on work done by John Dollan, and his far more complete version is at the ArcBuilder Site.

The original list, plus later versions, seem to have vanished from the web. There seems to be a partial copy available at

The list is split into Groups, Classes and Types. The top level groups are:

  • Belt Group - A collection of a large number of Small Bodies. This is a meta classification to denote a belt or ring around a star or planet.
  • Small Body Group - Includes small planetoids such as asteroids or coments, generally not more than 10s of kilometres in diameter.
  • Dwarf Terrestrial Group - Small rocky dwarf planets with a mass up to 0.15 of that of Earth. They are generally spherical and may have a trace atmosphere.
  • Terrestrial Group - Rocky worlds generally from 0.02 to 5.0 Earth masses. They may have geological activity (or had it in the past) and may have a substantial atmosphere.
  • Helian - Rocky worlds from 3 to 17 Earth masses which lack a layer of liquid or super-condensed volatives.
  • Jovian - Range in mass from 10 to 4,000 times the mass of the Earth, up to 13 times the mass of Jupiter. They have rocky or icy cores, and a thick atmosphere generally of hydrogen or helium.
  • Planemo - Planetary mass objects which are not bound to a star. Also known as rogue planets.
  • Construct - Artificially constructed objects of planetary scale or larger, from orbitals thousands of kilometres across to Dyson Swarms or Matrioshka Brains.




Dwarf Planets





Gaian Worlds

Arean Worlds




pcl.txt · Last modified: 2019/12/27 10:07 by sam