instance.add()
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
instance.add(source, parent?)
Setup and usage
Call for bounded gameplay events such as spawning a projectile, enemy, pickup, or effect. Avoid unbounded per-frame creation.
Parameters
| Variable | Type | Required | Description |
|---|---|---|---|
source | string | Yes | Source asset or stable scene path. |
parent | string or null | No | Destination parent stable entity ID; omit for the default root. |
Return and timing
Embedded Lua returns the new entity ID and creates immediately. JavaScript/Web and external SDK instance commands return no created ID and apply in command order at callback completion (or external query flush).
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
Use these snippets inside Start/on_start after generating the Programming Workspace and attaching the script. Python imports rustic, Game and instance from rustic; C++ includes rustic.hpp; C includes rustic.h; C# uses using static Rustic; Java runs inside a Rustic subclass; PHP declares global $rustic, $Game, $instance in its callback. HTML uses an inline script in a ui/ asset. See Lifecycle callbacks for complete registration examples. Public-property examples require a declared integer health property. Scene examples require the named objects to exist before Play.
Lua 5.4
instance.add('Part', nil)
instance.clone('Game.scene.Enemy',Game.scene.Find('Game.scene.Room'))JavaScript
instance.add('Part');
instance.clone('Game.scene.Enemy',Game.scene.Find('Game.scene.Room'));Python
instance.add('Part',None)
instance.clone('Game.scene.Enemy',Game.scene.Find('Game.scene.Room'))C++
instance.add("Part",std::nullopt);
instance.clone("Game.scene.Enemy", Game.scene.Find("Game.scene.Room"));C#
instance.add("Part",null);
instance.clone("Game.scene.Enemy", Game.scene.Find("Game.scene.Room"));Luau
instance.add('Part',nil)
instance.clone('Room.Enemy',Game.scene.Find('Room'))C
instance.add("Part",NULL);
instance.clone("Room.Enemy",Game.scene.Find("Room"));Java
instance.add("Part",null);
instance.clone("Room.Enemy",Game.scene.Find("Room"));PHP
$instance->add("Part",null);
$instance->clone("Room.Enemy",$Game->scene->Find("Room"));HTML / inline JS
instance.add('Part');
instance.clone("Game.scene.Enemy", Game.scene.Find("Game.scene.Room"));Shared Add & clone instances constraints
- Every gameplay language calls the engine-owned API. Rustic supplies SDKs and dispatches callbacks; scripts do not parse requests or serialize responses. See the language guide for complete setup and callback registration.
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.