# Raycast demo

click a cube in the grid to highlight the ray hit.

```{raw} html
<a class="example-run-button" href="../demos/features_3d_raycast.html">▶ Run in browser</a>

```

**Tags:** `3d`

Fires a world-space ray from the camera through the mouse cursor using
``screen_to_ray`` and intersects it against a ``CollisionWorld`` populated
with a grid of boxes. The ray and the closest hit are visualised with
``DebugDraw`` lines; the hit cube flashes yellow for a moment.

This is the manual-ray approach. For the engine's built-in GPU object-picking
buffer (``shape.pickable`` + ``on_picked``) see ``picking.py``.

Controls:
    Left mouse  - Cast a ray through the cursor
    Escape      - Quit

Run: uv run python examples/features/3d/raycast.py

## Source

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