# Volumetric Fog

Ray-marched single-scatter fog + localised FogVolume3D.

```{raw} html
<a class="example-run-button" href="../demos/features_3d_volumetric_fog.html">▶ Run in browser</a>

```

**Tags:** `3d`

Demonstrates:
  - Global volumetric fog driven by WorldEnvironment (density, anisotropy,
    albedo, height gradient): a single-scatter ray-march in HDR space.
  - A localised FogVolume3D box of denser fog modulating the global march.
  - A light shaft: a tight directional sun + forward-scattering anisotropy
    so the in-scatter haloes the light direction.

Controls:
    A / D        - Orbit camera left / right
    W / S        - Pitch camera up / down
    Q / E        - Zoom in / out
    1            - Toggle volumetric fog
    2            - Toggle the localised FogVolume3D box
    Up / Down    - Adjust global fog density
    Left / Right - Adjust anisotropy (forward/back scatter)
    Escape       - Quit

Run: uv run python examples/features/3d/volumetric_fog.py
     uv run python examples/features/3d/volumetric_fog.py --test

## Source

```{literalinclude} ../../examples/features/3d/volumetric_fog.py
:language: python
:linenos:
```