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

parts

7 mechanics, as Universe Sandbox does them

core · 2

physics & materials

Orbital mechanics

Newtonian n-body gravity acts between all bodies; the player edits mass, density, radius, and velocity and watches orbits, ejections, spin-apart breakup, and collisions follow.

time & pacing

Pause and speed control

Simulation speed runs from real time to years per second and can be paused; larger time steps trade against accuracy, so fast runs can diverge from slow ones.

supporting · 5

multiplayer & persistence

Content sharing

Player-made simulations are shared on Steam Workshop.

information & legibility

Data overlays

Orbit trails and surface temperature maps expose state that is otherwise invisible.

physics & materials

Heat transfer

Collisions and stellar irradiance heat bodies, shown as molten surfaces and temperature maps.

environment & ecology

Planetary climate

Surface temperature, sea ice, and oceans respond to stellar distance and axial tilt; moving a planet can freeze or boil it.

space & construction

Terraforming

Planets are composed from materials such as water, rock, iron, and gases, and oceans and mountains can be shaped.

core loop

load or build a system -> set masses, positions, and time step -> run gravity forward -> watch orbits, collisions, and climate respond -> tweak parameters or add bodies

design notes

Every body attracts every other under Newtonian n-body gravity, so the player can test questions such as what happens if a star passes the Solar System and see the answer rather than read it. The current version (a rewrite released as Universe Sandbox 2 in 2014 and renamed in 2018, still in early access) adds composition from a small set of materials, collisions that leave molten craters, and a climate layer where sea ice tracks axial tilt and oceans boil near a star. The simulation is an instrument for parameter sweeps; there are no goals or agents.

appears in

the paper, 2 sections · 2 chapters · 1 episode
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 1

Chapter 1. Same parts

linked from the text

book
ch 3

Chapter 3. Old parts

linked from the text

book
ep 1

Every simulation game is made of the same parts

on screen at 2:55 the most common parts

episode

sources

2
Wikipedia contributors (2026). Universe Sandbox. Wikipedia

provenance

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