Technical design programme
A city builder engineered to not collapse at scale.
Cities: Skylines 1 and 2 are performance-limited by architecture, not by effort. CS1 deletes vehicles that get stuck because per-agent replanning was never affordable. CS2 shipped rendering costs so mismatched to its content that it could not hold 30 FPS on high-end hardware. Both share one root cause: the cost model was discovered late. Infrastruct allocates the frame budget before writing the system.
North star
- 1,000,000simulated citizens
- 250,000concurrent vehicles
- 60FPS, locked, mid-range PC
- 0despawns · teleports · sim-speed collapse
Phase roadmap
Eleven phases. Each one closes only when its exit criteria are measured, not asserted.
Work board
What is done, in flight, and queued right now.
Architecture decisions
Every decision of consequence is recorded, with the trigger that would reopen it.
The document
The design document is compiled from the Markdown sources into a single typeset PDF. It grows as phases are added — high-level summaries for every phase, what each one delivers, what remains after it, and the step-by-step build plan with the AI prompts used to execute it.