# SubViewport

render a live 3D scene to a texture, shown on an in-world monitor.

```{raw} html
<a class="example-run-button" href="../demos/features_3d_sub_viewport.html">▶ Run in browser</a>

```

**Tags:** `3d` `subviewport` `render-to-texture`

A SubViewport renders its own subtree (a spinning cube on a blue background,
viewed by its own Camera3D) into an offscreen texture every frame. That texture
is fed to a Material on a flat "monitor" slab in the main scene: a live screen
in the world. The monitor's feed updates each frame, proving the render-to-
texture is genuinely live, not a one-shot capture.


Usage:
    uv run python examples/features/3d/sub_viewport.py
    uv run python examples/features/3d/sub_viewport.py --test

## Source

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