one dataset · paper, tables, graph, wiki
simgrammar the grammar of simulation

parts

10 mechanics, as SimEarth does them

core · 3

control & automation

God powers

Placing terrain, life, monoliths, oxygen generators, and terraforming devices costs energy (50 per terrain square, 500 per device) from a budget that grows with planetary development.

population & lineage

Natural selection

Taxa from prokaryotes to mammals spread and diversify by environment, with player-set reproduction and mutation rates; mass extinctions are often followed by renewed radiation, and any multicellular taxon can become sapient.

environment & ecology

Planetary climate

Atmospheric composition, temperature, ocean level, and biomes evolve together under Gaian feedback; volcanic dust cools, warming melts ice caps, extreme heat boils oceans, and Daisyworld reduces it to daisies regulating temperature.

supporting · 7

information & legibility

Data overlays

environment & ecology

Habitat suitability

environment & ecology

Pollution spread

risk & failure

Random disasters

Hurricanes, wildfires, earthquakes, tsunamis, and meteors occur, with disease and pollution scaling with population.

progression & goals

Scenario objectives

space & construction

Terraforming

Mars, Venus, Ice Planet, and Dune scenarios ask the player to make hostile planets habitable.

core loop

set geological, atmospheric, and biological rates -> climate and biomes evolve -> taxa spread, mutate, and diversify -> one sapient species advances through seven ages -> pollution, war, and disasters feed back on climate -> spend energy on interventions

design notes

Will Wright and Fred Haslam built SimEarth with James Lovelock as adviser, and its models encode Gaian feedback: volcanic dust cools the planet, warming melts ice caps and raises seas, and life alters atmospheric gas fractions shown to three decimal places. The player mostly acts through control panels that set rates such as continental drift, reproduction, and mutation, plus energy-priced interventions (50 units per terrain square, 500 per terraforming device), so play is closer to tuning coupled systems than to directing agents. Scenarios include Daisyworld, Lovelock's minimal model of temperature regulation by daisy color, and terraforming Mars and Venus.

appears in

the paper, 2 sections · 2 chapters
paper

5. The structure of the design space

linked in this section of the paper

paper
paper

Appendix A. Game catalog

linked in this section of the paper

paper
catalog

The catalog

listed with its year, developer, subgenre, and number of mechanics

book
ch 2

Chapter 2. Six layers

linked from the text

book
ch 4

Chapter 4. Families

linked from the text

book

sources

1
Wikipedia contributors (2026). SimEarth. Wikipedia

provenance

runs in log/runs
2026-10-24
created2026-10-24-catalog-gdcatalog