Ue Uds Time

UDS time of day

UDS has a single canonical time variable, three categories of runtime control (set / animate / transition), four getter functions, and a complete event-dispatcher system for game logic that needs to react to time. For real-world astronomical positioning (lat/long/date), see ue-uds-simulation.

When to use this skill

• Setting up a day/night cycle.
• Triggering game events at sunrise, sunset, midnight, hourly, or arbitrary custom times.
• Setting time programmatically from gameplay code (instantly or as a transition).
• Reading the current time in HH/MM/SS form, or just checking "is it day".
• Putting a clock on screen.
• Syncing game time across multiplayer.

Setting the time

Time of Day is a float on UDS, 0–2400, in the Basic Controls category. You can also type a string like "3PM" or "15:45" into Time of Day String. Setting Time of Day directly at runtime instantly changes the time.

Animating time (day/night cycle)

In the Animate Time of Day category, enable Animate Time of Day. Then:

When Simulate Real Sun is enabled (see ue-uds-simulation), Day Length / Night Length are ignored — speed comes from Simulation Speed in the Simulation category (1 = roughly real-time).

Runtime control functions

Get a UDS reference with the shared Get Ultra Dynamic Sky function. Then call:

Direct UDS.TimeOfDay = X also works for instant changes.

Sampling the current time

Is It Daytime? is the right call when you only need day-vs-night, not the exact time.

Display widgets

Two clock widgets in the widget designer palette under Ultra Dynamic Sky Widgets. Drop into a UMG widget for a quick on-screen clock.

Event dispatchers

Bind events from your blueprints. Pattern:

Copy code
UDS = GetUltraDynamicSky()
UDS.OnSunrise.AddDynamic(this, &MyActor::OnSunrise)
// Or in Blueprint: Bind to Sunrise → Custom Event

Offsetting Sunrise / Sunset

Sunrise Event Offset and Sunset Event Offset in Animate Time of Day shift the trigger minute relative to the actual horizon cross.

Event check frequency

Time Event Dispatcher Check Period (Animate Time of Day) — how often the dispatcher logic checks for triggers. Default: every second whenever Time of Day is actively changing.

Hourly vs Current Hour Changed

If a fast Transition Time of Day skips from 14:00 to 18:00:

Custom Time example

In Animate Time of Day, set Custom Time Dispatchers to [630, 1230, 2200]. Bind to Custom Time. The bound event fires:

Use the index in a Switch to branch per scheduled time.

Material functions for time

Search the material palette:

Good for materials that switch (e.g. emissive on at night) without involving a blueprint. For light components that turn on at night (not just materials), use the Light Day/Night Toggle component — see ue-uds-lighting-and-shadows.

Sequencer

To keyframe Time of Day in Sequencer:

1. Disable Animate Time of Day on UDS (otherwise it overrides your keys).
2. Keyframe Time of Day directly. Going past 2400 is fine — UDS rolls into the next day.

Many UDS variables are exposed for cinematics, but not all are re-applied dynamically every frame. If a keyframed value doesn't update at runtime, mark it Expose to Cinematics in the UDS blueprint and call the matching Static Properties - <Category> function each frame. (Weather state has its own Sequencer notes — see ue-udw-setup-and-state.)

Multiplayer replication

Time of Day and Date are replicated.

Clients tick time locally between resyncs the same way the server does. Brief desync between resyncs is normal; the periodic Replicated Time of Day update realigns them.

Gotchas

• Time of Day won't change at runtime — the sun is static or stationary mobility. Time-of-day cannot change at runtime with non-movable sun. See ue-uds-lighting-and-shadows.
• Keyframes in Sequencer have no effect — Animate Time of Day is still on and overriding. Disable it.
• Sunrise/Sunset firing at the wrong time — Simulate Real Sun is on, which uses real horizon crossing rather than Dusk Time / Dawn Time. (See ue-uds-simulation.) Or there's a Sunrise/Sunset Event Offset configured.
• Hourly firing many times after Transition Time of Day — that's Hourly's intended behavior (every hour passed). Use Current Hour Changed for "once for the new hour".
• Custom Time never fires — Custom Time Dispatchers array is empty. Add values.
• Animation speed feels wrong despite Day Length / Night Length — Simulate Real Sun is enabled and overriding to use Simulation Speed instead.

References & source material

Docs (Ultra Dynamic Sky 9.5):

• Controlling Time of Day (incl. Animate Time of Day, time-control functions)
• Getting and Displaying Time of Day
• Triggering Events at Specific Times (dispatchers)
• Sky Utility Material Functions (Day to Night, Active Sun or Moon Vector)
• Technical Notes — Replication (UDS)

Plugin asset paths:

• Blueprints/Utilities/ — Light Day/Night Toggle component (the light-component partner of the material Day to Night functions)
• Widget designer palette → Ultra Dynamic Sky Widgets category — clock widgets

Related skills: ue-uds-simulation, ue-uds-sun-moon-stars, ue-uds-lighting-and-shadows, ue-uds-cinematics-rendering, ue-udw-setup-and-state.