Rules Index | GM Screen | Player's Guide

Chapter 2: Tools / Building Worlds

The World

Source Gamemastery Guide pg. 122
While world building might include building much more than a single planet, most adventures occur entirely on one world. It’s a good idea to have a broad understanding of that world as a whole.

Planetary Basics

Source Gamemastery Guide pg. 122
When designing the physical features of a campaign world, you’ll want to determine its shape and the general distribution of landmasses. You can also establish the world’s size, though note the scale of a world generally has a fairly small impact on the adventures taking place there.


Source Gamemastery Guide pg. 122
In a fantasy setting, the shape of your world need not be spherical as governed by the laws of physics. It could be any shape you desire, and it need not be a planet at all!

Globe: Barring some catastrophe, worlds in our reality are roughly spherical due to the influence of gravity.

Hollow World: What if the landmasses and civilizations of a world existed on the inner surface of a hollow sphere? In such a world, the horizon would climb upwards, permitting creatures to see landmarks at extraordinary distances. Light might emanate from a sun‑like orb in the world’s center, from various other natural or magical sources, or not at all.

Irregular: What if your world is flat, a toroid, or shaped into a cylinder, cube, or other polyhedron? What if it’s something even stranger? With such an unusual shape, you may need to decide how gravity, atmosphere, and other details function.


Source Gamemastery Guide pg. 123
The next major step in world creation is to sketch out the planet’s oceans and major landmasses. On Earth, these geological features are the result of plate tectonics. In a fantasy world, however, the oceans might have been cleaved from the land by the actions of titans, or the continents shaped to suit a god’s whims. The following are some common landmass types.

Archipelago: A stretch of vast ocean, dotted by chains of small island groups, atolls, and islets.

Major Islands: A region of seas dominated by large islands, each several hundred miles across.

Island‑Continent: An enormous island nearly the size of a continent, surrounded by ocean.

Continent: A substantial landform that (usually) rests on a tectonic plate and gradually shifts in position over geologic timescales.

Supercontinent: An assembly of the world’s continental blocks into a single immense landmass.


Source Gamemastery Guide pg. 123
The environment and terrain of a region can pose as much of a challenge to an adventuring party as any of the foes they face. The following section references the environment categories beginning on page 512 of the Core Rulebook.

Common Environments

Source Gamemastery Guide pg. 123
The following environments are common enough that they might appear in nearly any adventure or world.

Aquatic: Oceans, seas, lakes, and other large waterways are aquatic environments.

Arctic: Arctic environments usually appear near the northern and southern extremes of a world, though extreme elevation, unusually shaped worlds, and supernatural forces could result in arctic terrain elsewhere.

Desert: Deserts can appear anywhere on a world where precipitation is scant, even along some oceans. Any large landmasses that entirely lack bodies of water are likely to be deserts.

Forest: The composition of a forest depends on the climate and the elevation, with thick jungles more common near an equator, hardwood forests in more temperate zones, and evergreens at higher latitudes and elevations. Most worlds have a tree line—an elevation above which trees can’t grow.

Mountain: A world’s highest peaks can stretch tens of thousands of feet above sea level. This category also includes hills, which are typically no more than 1,000 feet tall.

Plains: Mostly flat and unobstructed, plains are usually at lower elevations, but they can also be found at higher elevation on plateaus.

Urban: Cities and settlements are urban environments. These areas are detailed in Settlements, beginning on page 132.

Swamp: Wide floodplains, shallow lakes, and marshes can appear at most latitudes.

Extreme Environments

Source Gamemastery Guide pg. 123
Some adventures lead to fantastic reaches of the world or the multiverse that are seldom tread by mortals.

Aerial: A world might include windy realms of floating islands and castles in the clouds.

Glacier: Massive sheets of dense ice, constantly moving under their own immense weight, glaciers are frozen wastelands riddled with columns of jagged ice and snow‑covered crevasses.

Volcanic: Hellish landscapes of molten lava, burning ash, and scorching temperatures pose immediate danger.

Undersea: A subset of aquatic environments, undersea environments are those areas submerged beneath the waves.

Underground: Some worlds have deep natural caverns, while others have extensive winding tunnels and expansive realms below the surface.

Mapping a World

Source Gamemastery Guide pg. 123
Many Game Masters like to have an overland map for their local region, nation, or even the whole world. The primary goal of this scale of map is to designate sites of import to the campaign; you need not detail every hamlet or woodland grove, but having a sense of the major features can help you and the other players visualize the world in which they’re playing.

Step 1. Coastlines: The easiest first step is to separate land from sea. Regional maps may only have a single shoreline, if any. At larger map scales, consider the placement of major islands, archipelago chains, atolls, and islets. A world map should consider the size and placement of continents.

Step 2. Topography: Pencil in a rough ridgeline for each mountain range in the region. Mountain ranges are common along coastlines where continental plates push together. If extended into the sea, mountain ranges typically result in a chain of offshore islands. Indicate hills in the regions adjacent to the mountains and elsewhere as necessary to demonstrate elevation. Unmarked terrain on an overland map is usually lowland plains.

Step 3. Watercourses: It’s important to keep in mind that rivers flow downstream, from high elevation toward the sea, always taking the path of least resistance. Powerful watercourses might carve canyons or gorges over millennia, but they should never cross through mountain ranges. On a similar note, watercourses don’t branch—tributaries join into rivers as they flow downstream.

Step 4. Terrain and Environment: Sketch in interesting terrain features such as forests, deserts, or tundra. You may want to differentiate these environs, separating coniferous and deciduous forests from tropical jungles or arctic taiga. Environs not specifically called out on an overland map are typically presumed to be some variety of grassland.

Step 5. Civilization: Now you’re ready to place the elements of civilization. Major cities should typically be located near fresh water and natural resources. Major roads connect larger settlements, circumventing forests and other difficult environs, but they may wind through mountain passes when lucrative commerce demands it. Add smaller settlements along your roads, further connected by smaller roads and trails. Finally, draw political boundaries and mark other sites of interest.