> ## Documentation Index
> Fetch the complete documentation index at: https://dadd.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# useSceneLights

> Hook for creating Three.js lights from MJCF definitions

Creates Three.js lights from MJCF `<light>` elements in the loaded model. Hook form of [`<SceneLights>`](/components/scene-lights) for imperative usage inside your own components.

## Signature

```tsx theme={null}
useSceneLights(intensity?: number): void
```

## Usage

```tsx theme={null}
import { useSceneLights } from "mujoco-react";

function MyScene() {
  useSceneLights(1.5);
  return <mesh />;
}
```

### Composing with Custom Lighting

```tsx theme={null}
function SceneSetup() {
  useSceneLights(0.8); // MJCF lights at 80% intensity

  return (
    <>
      {/* Add your own supplementary lights */}
      <ambientLight intensity={0.2} />
      <pointLight position={[5, 5, 5]} intensity={0.5} />
    </>
  );
}
```

## Parameters

| Parameter   | Type     | Default | Description                                       |
| ----------- | -------- | ------- | ------------------------------------------------- |
| `intensity` | `number` | `1.0`   | Multiplier applied to all MJCF light intensities. |

## Light Mapping

| MJCF `light_type` | Three.js Light     |
| ----------------- | ------------------ |
| `0` (directional) | `DirectionalLight` |
| `1` (spot)        | `SpotLight`        |

## How It Works

1. On model load, reads `model.nlight` and iterates all MJCF light definitions
2. Creates `DirectionalLight` or `SpotLight` instances based on `light_type`
3. Applies position, direction, color, shadow, and attenuation from model data
4. Lights are added to the R3F scene and cleaned up on unmount or model change

## Notes

* For a declarative JSX API, use [`<SceneLights>`](/components/scene-lights) instead
* The component form is a thin wrapper around this hook
* If the MJCF model has no `<light>` elements, this hook does nothing