Farm¸ Forge and Steam (d20)
Farm¸ Forge and Steam is a campaign design aid for GMs who want a realistic and logical background.
It provides information and guidelines for key areas of campaign design including -
* Population distribution and growth
* Diseases and Demographics (the biggest retarding factor on pre-modern population growth after food supplies)
* Food sources¸ productivity and supply (how many people are needed to grow the food¸ and how many non-farmers they can support)
* Transport effects (or why the biggest metropolises are port cities)
* Technology effects (or why even magic can't prevent technological progress)
* Magic effects (how magic would really affect a world over a long period of time)
* Common design faults and mistaken assumptions (why technological and social stasis for millennia doesn't work¸ why "universal empires" don't make much sense¸ and why its a bad idea to price technology for "game balance" reasons... and unneccessary to boot).
If you are designing a new campaign world¸ or overhauling an existing one (whether commercially published or home brew)¸ then you can't go far wrong by using FFnS to ensure that the whole creation hangs together.
Farm¸ Forge and Steam is usable with *any* game system¸ as it is a *meta* product... it provides the underpinnings for the campaign without affecting the actual game system.
The "rules" that are detailed in Farm¸ Forge and Steam are general ones¸ not universal mathematical formulae (though some of them come with mathematically applicable data)¸ and enable you to provide broad and medium level application for your campaign.