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simgrammar the grammar of simulation

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Short 7: Most used, barely touched, opening frameplay · 0:36
rendered · short-07.mp4 · drawn from the dataset

short 7 0:36

Most used, barely touched

transcript

The kind of mechanic simulation games use most is among the kinds AI research has touched least.

Resources and production is the most used family in our catalog. Of its 14 mechanics, 12 have no AI technique pointed at them, production chains included.

A furnace starves far upstream, and the player blames the building in front of them. The record for production chains lists that as a known failure in games without flow statistics.

Instead the techniques pile up on stories and characters. Narrative and generation is the most exposed family in the set.

also on the pages for

definition

Belts form directed chains of tiles; each tile holds a fixed number of item slots per lane and moves items forward at a tier-dependent speed. Items enter from inserters, machines, or side-loading and exit at the end, onto another belt, or into a machine. Splitters divide and merge flows, often with priority and filter settings; undergrounds and bridges cross other belts. Factorio holds 4 items per lane per tile and carries 15, 30, 45, or 60 items per second across both lanes for transport, fast, express, and turbo belts. Internally it groups adjacent belts into transport lines and stores the gaps between items, so a free-flowing line updates only its end gaps each tick. Satisfactory, Dyson Sphere Program, and Mindustry use similar belt tiers, and Shapez raises belt speed through upgrades. Inputs: items placed on belts. Outputs: items delivered at a throughput capped by the slowest segment.

player experience

Layout as the main puzzle. Players route belts around each other, balance lanes, and design compact buses, and they can see throughput problems as gaps or backed-up lines. A compressed belt feeding a full row of machines is a visible proof of a correct design.

design levers

  • throughput per tier and number of lanes
  • splitter, merger, and priority or filter options
  • crossing options such as undergrounds, bridges, or vertical lifts
  • item density and whether mixed items share a lane
  • belt cost and unlock schedule

failure modes

  • Spaghetti layouts become unreadable and players stop understanding their own factory.
  • Lane imbalance and side-loading rules are opaque without wikis.
  • Belt counts at large scale cost simulation time; Factorio's transport-line rewrite was made to cut this cost.

dynamics

  • Main-bus and ratio-block conventions emerge from throughput caps, and players share them as blueprints.
  • Belt saturation sets factory module sizes, so each tier upgrade reshapes layouts.
  • Mixed-item belts create sushi designs and clogging failure modes.

open questions

  • Could layout assistants that propose belt routing under player constraints keep the puzzle while removing tedium?
  • What is the smallest set of belt primitives that still supports deep layout optimization?

appears in

the paper, 2 sections · 4 episodes · 1 short
paper

4. A grammar of simulation games

linked in this section of the paper

paper
paper

5. The structure of the design space

linked in this section of the paper

paper
glossary

Glossary of mechanics

listed under logistics & networks, with its summary

book
ep 2

Where the parts came from

on screen at 5:18 after 2000, 7:21 built from older parts

episode
ep 3

Families across genres

on screen at 0:17 cold open, 0:27 same chain, different games, 5:12 series and descendants

episode
ep 9

Bets worth making

on screen at 0:00 cold open, 0:25 a tool that names the cause

episode
ep 10

What breaks

on screen at 1:05 same inputs, same world

episode
short 7

Most used, barely touched

0:36 · on screen in the short

short

relations

1 stored edges
synergy

Production chains

Belts make recipe chains spatial, turning ratios into a layout puzzle (Factorio, Satisfactory).

sources

2
Harkonnen (2017-02-03). Friday Facts #176 - Belts optimization for 0.15. Factorio blog (Wube Software)
Factorio Wiki contributors (2026). Transport belts/Physics. Official Factorio Wiki

provenance

runs in log/runs
2026-10-24
created2026-10-24-taxonomy-m1taxonomy