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

# Box Selection

Making your own extension is a powerful feature of the viewer. In this example we've made a box selection feature by implementing our own extension.

<Frame caption="Box Selection Example">
  <iframe src="https://stackblitz.com/edit/speckle-box-selection?embed=1&file=src/main.ts&view=preview&hideExplorer=true&hideNavigation=true" height="500" style={{ width: '100%', border: 0 }} allowFullScreen />
</Frame>