Why emergency lighting is hard
Emergency vehicle lighting looks simple and is not. A real light bar runs multiple independent heads on different flash patterns, each with its own colour, timing and phase relationship to the others. Getting this wrong is immediately obvious to anyone who has seen the real thing, and the roleplay audience is unusually well informed about exactly this detail.
The naive implementation is a script per light toggling transparency, which produces a plausible result for one vehicle and destroys frame rate once twenty of them are on screen. Project Beacon is the answer to doing it correctly and doing it at scale simultaneously.
Patterns as data
Beacon describes a lighting configuration declaratively. A profile defines the heads present on a vehicle, their positions and colours, and the patterns available to them, with patterns expressed as timed sequences rather than as code. Adding a new agency livery is authoring data, not writing another script.
Because patterns are data, they can be validated, previewed and shared. Police, Fire, EMS, DOT, utility and tow profiles all draw from the same pattern library while differing in colour and head layout, which is broadly how the real equipment works.
One controller, many lights
The performance work is in the update model. Rather than each light running its own timer, a single controller advances all active patterns on one clock and applies the resulting state in batches. Lights that are off-screen or beyond a distance threshold drop to a reduced update rate or stop updating entirely, since a light bar two hundred studs away does not need per-frame accuracy.
Emissive surfaces, actual light sources and volumetric cones are treated as three separate levels of detail on the same light. Nearby vehicles get all three, mid-distance vehicles keep the emissive surface and the light, and distant vehicles keep only the emissive surface. The transition is tuned to be invisible in motion.
Beyond vehicles
The same framework drives environmental lighting: street lights that respond to the day cycle, headlights that react to conditions, and interior lighting that changes with weather. These share the controller and the level-of-detail system, so a city at night costs a fraction of what it would with independently scripted fixtures.
Time of day and weather feed in as inputs rather than being handled per-fixture, which means a single change to the environmental state propagates correctly through every light in the world without any fixture needing to know about the others.