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DOCSENGINEAPI REFERENCECLOCKCLOCK.TIMESCALE()

Clock.timeScale()

Clock

Compatibility

Supported languages: C, C++, C#, Python, JavaScript, Lua 5.4, Luau, Java, PHP and HTML/inline JavaScript (binding spellings and return shapes differ).

Use a compatible native engine build and the language tools required by your binding. This does not establish browser/mobile export or release qualification for every OS.

The signature below is the shared reference notation; language examples show the actual binding syntax. Question marks mark optional arguments and explicit defaults are shown where recorded. Do not copy reference notation as a typed declaration.

See Feature status and compatibility for API 1.0/1.1 and per-method restrictions. Engine release tags and Docs v0.1 are independent versions.

Signature

Clock.timeScale(scale)

Setup and usage

These engine-owned services work in Lua 5.4, Luau, JavaScript, Python, C, C++, C#, Java, PHP, and HTML inline JavaScript. Follow Use gameplay actions to create and attach a script, install external toolchains, and choose the correct language binding. PHP and HTML scripts belong under ui/; CSS alone runs no gameplay code.

The Calls section uses JavaScript signatures. The function examples below include native syntax for all ten script types, including SDK-specific alternatives and limitations. Attach a JavaScript Object Component script to the specified target and press Play. Globals are supplied by the engine. Schedule actions from Start or a callback, rather than at script top level. Native languages use typed options and their own builder conventions; see the guide's language bindings.

Parameters

Scale is finite non-negative; 1 is normal rate and 0.5 is half speed. Clock.state() returns the current scale and paused flag in every gameplay language. C returns RusticClockState; C++ returns RusticValue; C# returns JsonElement; Java returns a map. C sets time scale with Clock.timeScale(value) and reads it with Clock.state().scale.

Return and timing

TimeScale returns the resulting scale in JavaScript; state returns a synchronous clock snapshot. Pause/resume change global clock state rather than creating an operation handle.

Execution behavior

Core write timing differs between immediate Lua host calls, deferred JavaScript/Web commands and external SDK query flushes. Scheduled actions advance with the scene clock; synchronous queries evaluate at the call. Follow execution rules and the return/timing notes for this category.

Language examples

Choose one snippet at a time and place it inside your language's Start/on_start callback. These are independent examples; each creates its own handles or builders. Follow Gameplay language bindings for imports and callback registration. Python must import the modules used in its snippet from rustic; C# uses using static Rustic; Java examples belong inside a Rustic subclass; PHP callbacks declare global $rustic. HTML snippets go inside an inline script in a ui/ HTML asset.

Use an anchored Part for transform and effect examples, an unanchored collidable Part for forces, and a perspective camera named Camera for camera examples. Create Target for follow examples. Audio examples require assets/music.ogg in the Play snapshot. Replace scene paths with those listed by Game.scene.List(). Animation playback and sequence-animation examples require the Reveal fixture on the Animation page; marker callbacks also require its Halfway marker. Run clock controls separately; a paused clock cannot advance a timer.

C callback examples use these file-scope functions before on_start:

c
static void on_done(void) { rustic.log("info", "done"); }
static void on_sample(RusticValue value) { (void)value; rustic.log("info", "sample received"); }
static void on_event(const RusticValue *args, size_t count) {
    (void)args; (void)count; rustic.log("info", "event received");
}

Lua 5.4

lua
Clock.timeScale(0.5)

Shared Clock constraints

  • An anchored Part takes about four real seconds to finish the two-scene-second tween, then restores normal speed.
  • Scaling applies to action/timer time, clip source clocks, physics and audio playback. Clip blend durations are scene-clock seconds.
  • Clock.pause leaves script lifecycle callbacks available so a controller can call resume. A Timer alone cannot resume a paused clock because its own time is frozen.
  • Play pause freezes the runtime; Stop discards it. Per-operation pause and voice.pause affect only their respective operation/voice.
  • Check script attachment, enabled state and the Console when an operation fails. Asynchronous errors also appear in operation state. Callback exceptions disable the owner and clean up its actions.
  • Owner destruction, disable, successful reload or Stop cleans up owned actions and subscriptions. Failed reload retains the previous behavior's operations. See Operation handles for controls and lifetime details.

Errors and debugging

Read the constraints above and the Console diagnostic. Invalid types, non-finite values, stale targets or unavailable native services can fail validation. A failed callback disables the behavior; a failed source reload keeps the last good instance. Exact error messages depend on the language adapter. See Troubleshooting.

All clock APIs