From systems to a game

What each system supplies, the job it does in the game, and what it cannot supply

The systems describe Griffintown. A game needs them for four jobs: a world to stand in, people moving through it on time, places where something can happen, and a way to check the result. Each system does one of these jobs first. This page says which, with the counts each system holds today.

I treat the move from a system to the game as a translation. A system is the source. Each decision that turns part of it into a game element is written down, with its kind (source observation, researcher decision, assumption or gap) and an alternative. The first part of that translation is built: G1 World (verified). The game is built from it in stages (The game, stage by stage).

Four jobs

Job	What the game needs	Systems	What no system supplies
World	ground, buildings and objects to stand among	S1, S4, S6	roofs, facades, interiors, terrain, entrances
Rhythm	people and vehicles that move by rules, at the right hours	S3, S5, S7, S9	every trip besides a commute; evenings; weekends on foot
Points	places where people could stop or gather, or the player could act	S4, S5, S6, S7, S8	any record of people gathering
Check	measures the game’s movement is compared with	S2, S5, S9	counts beyond seven junctions and 23 sites

S5 appears twice on purpose. Its opening hours time the people in the game. Its counts stay out of the game, so they can check it.

World

These systems become the ground and the masses the player moves among. The NPCs, the people and vehicles the game moves by its own rules, use the same ground.

System	Supplies	In the game	Translation decision	Gap
S1 Streets	264 segments and 191 junctions, each with walk and car flags	the walkable and drivable ground, as a graph	taken as filed, no path added (W03, researcher decision)	paths nobody filed: the canal path and park paths found in S1’s checks
S4 Buildings	296 outlines; storeys for 223; a measured height for 27; uses	building masses with a height and a door	234 heights measured, most from the city’s 2015 surface model; 48 from storeys (W05, assumption); 14 left empty (W06)	entrances, roofs, facades, interiors
S6 Streetscape	2,898 object rows, among them 971 trees, 806 street lights and 101 benches; 487 sidewalks and 32 islands	2,783 props and the sidewalk surfaces	one prop per physical object (W09, researcher decision)	private trees, canopies, how each object is used

Rhythm

These systems would run the NPCs: who is out, when, by which mode, under which rules, and by which route. A city’s rhythm in the game can only be as complete as these sources. Today they cover commuting on a weekday morning.

System	Supplies	In the game	Translation decision	Gap
S3 Rules	86 banned moves out of 578; 34 signal lights at 32 junctions; 493 sign panels; a speed limit for each of the 227 drivable segments	what NPC drivers may do at each junction, and how fast	planned: rules obeyed as filed; light timing estimated from the counts where the city counted (Movement counts), an assumption elsewhere	light timing at most lights; whether the rules are kept
S5 Rhythm	opening hours read for 82 places	when shops and services open their doors to NPCs	planned: a place with no hours stays closed to NPC visits, and says so	hours of the other 527 places
S7 Commuters	about 7,200 commuters living in 132 residential buildings, by mode and by hour of leaving; 295 transit stops	how many NPCs leave home, by what mode and at what hour	planned: one NPC per commuter or a stated fraction	errands, school runs, visitors, people passing through
S9 Observer	16,958 weighted trips of commuters on foot, routed under three route rules, resting on 13 assumptions	the route each NPC takes	planned: the route rule chosen per run and shown to the player	most of the people counted on the street (S9 holds about a quarter at 7 and 8 h)

Points

These systems mark places where people could stop, wait or gather, and where a player could act on a building or an object. No source records people gathering, so every point is a candidate.

System	Supplies	In the game	Translation decision	Gap
S4 Buildings	610 places: 425 inside buildings, 118 next to one, 67 outside any (parks, pitches, playgrounds); 83 with hours	destinations and doors a player could use	buildings with a recorded public use marked: 172 of 296 (W08, assumption)	what a place means; what happens upstairs
S6 Streetscape	101 benches, 31 picnic tables, 4 water points, 2 shelters, 110 bike racks	places to sit, wait or lock a bicycle	planned: each is a candidate stop for an NPC	whether anyone sits there
S7 Commuters	27 bus stops inside the area; 22 metro entrances nearby	places where NPCs wait	planned: waiting time from the STM timetable	the queue itself
S5 Rhythm	7 counted junctions; 23 counted sites around the area	corners known to be busy at counted hours	planned: marked as measured busy points	lingering, which no count records
S8 Views	1,798 viewpoints with what each can see	where a view opens or closes along a route	planned: open views as candidate pauses	attention; what blocks a view besides buildings

Check

These systems stay outside the game’s decisions, so the game can be compared with them. A measure used to steer the NPCs can no longer test them.

System	Supplies	In the game	Translation decision	Gap
S2 Scores	space syntax values for 257 of 264 segments on foot, 227 by car	a measure the NPC and player routes are compared with	researcher decision: NPCs do not read it (the same rule as S9). An NPC rule that uses it would be a separate, labelled reading	7 segments without a walking value (Autoroute 10 and its ramps); the 37 closed to cars have no vehicle value, by rule
S5 Rhythm	counts by hour at 7 junctions on 9 weekdays; 376 bicycle days	the counts a game day is compared with	planned: the game counts at the same junctions and hours	weekends and seasons on foot
S9 Observer	its ledger and its comparisons	the template for comparing a game run	planned: each game run gets a ledger like S9’s	the comparison of play with residents’ accounts

The prototype

The data side of the translation is built as code next to the systems: G1 World reads the systems’ outputs, writes files any engine can read, and keeps a ledger and tests (verified: 10 tests pass). The game is built from those files in stages, starting with one building and one route (The game, stage by stage). The engine: G7 Engine.

What no system gives the game

Two kinds of knowledge are missing from every system. Griffintown in the 1920s to 1940s needs historical maps and records. What residents know needs interviews and focus groups, after research ethics approval. Until then, the game can hold Griffintown’s present layout and its weekday commute, and every other part of its rhythm is an assumption the ledger names.