Two clocks

Some PlaneSim worlds run at real time; others run an accelerated clock that keeps moving while you sleep. What a 4x world does to a player's week, and why the engine never lets game time and wall time touch.

Every PlaneSim world keeps two kinds of time, and the engine is built so they can never be confused. There is wall time, the ordinary clock on your desk. And there is game time, which advances at a configurable multiple of real time, continuously, whether or not you are logged in.

That second clause is the one that shapes the game. A PlaneSim world is not paused between your sessions. It is a shared, always-on economy, and your airline lives in it around the clock.

What 4x does to your week

Take a world running at 4x, the example we use throughout the docs. One real day carries four game days. Sleep eight hours and your airline has flown a full game day and part of the next without you. A real week is roughly a game month.

This is why PlaneSim sessions look the way they do. The game is designed for recurring desk sessions: you open the world, read the overnight results, adjust schedules and fares, react to whatever your rivals did while you were away, and close the tab knowing the world will keep going. Demand is recalculated every game day, so at 4x the market has re-priced itself four times since yesterday's session. Weekly profit periods come around every couple of real days. The rhythm is closer to checking on a business than to sitting down for a play session, and that is deliberate.

The acceleration has a sharp edge, and we would rather name it than hide it. Things happen without you. A rival can open a route against you on Tuesday game time while it is 3 a.m. at your desk. The news feed, notifications, and the live map exist precisely because the world does not wait: they are how a returning player reconstructs what the world did in their absence. And the multiple itself is per-world configuration, not a universal constant, so a world's pace is a property you can read before you commit an airline to it.

The pause that costs nothing

There is one situation where game time stops: when the world's server itself stops, for a deploy or a migration. Here the two-clock design earns its keep. Downtime is a pure pause. When the world boots again, the engine re-anchors the game clock to the present and resumes at exactly the tick where it stopped.

The alternative would be a catch-up storm: a server that comes back and fast-forwards through the missed hours, hammering through game days while players watch numbers blur past. PlaneSim never does this. An hour offline costs an hour of wall time and nothing else. No game days are lost, none are compressed, and nobody's overnight results were computed in a panic. This property is a large part of why we could move a running world between servers without the economy noticing.

Never merge the clocks

Inside the engine, the two-clock rule hardens into an invariant: every number is keyed to exactly one clock, and numbers keyed to different clocks are never merged.

Everything the simulation produces lives on the game clock. A week of route profit is a game week. A daily demand recalculation is a game day. An aircraft's age, a loan's term, a season's length inside the world: game time, all of it. Everything about operating the service lives on the wall clock: server uptime, deploy windows, the real-world date on a news post.

The reason for the rigidity is that mixed-clock numbers do not look wrong. They look plausible and are off by the world's multiplier. At 4x, an aggregate that accidentally binned game-time events by wall-clock days would report figures inflated fourfold, smoothly and consistently, the kind of error that survives a glance and poisons every decision made on top of it. So the engine treats the clocks as separate axes end to end. A statistic declares its clock the way a value declares its currency, and there is no exchange rate.

The world outlives the pause, not the season

One more consequence of taking time seriously: worlds end on schedule. Each world posts a finite season up front, most running two, six, or twelve months, and closes when the season is over, into a permanent archive rather than oblivion. The clock that never waits for you also never runs forever, and we think a world with a posted ending makes every game day inside it count for more. The full rules of the simulation those days run under are in the player wiki, written from the engine's code.