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

# Cuboid Tool

> Draw pseudo-3D cuboid annotations on 2D images in PixlHub: two clicks for the front face, one for depth, Enter to finish.

Some models need more than a flat rectangle: vehicle pose, parcel dimensions, furniture orientation. The Cuboid tool draws a pseudo-3D box on a 2D image: a front face plus projected depth edges, giving downstream models the geometry a bounding box throws away.

<Info>
  Cuboids annotate perspective on flat images. For true 3D boxes on point clouds, that is the LiDAR editor's territory with a dedicated project type.
</Info>

## Draw a cuboid

<Steps>
  <Step title="Arm the class and pick the tool">
    Press the class hotkey, then click the cuboid icon in the floating palette.
  </Step>

  <Step title="Two clicks for the front face">
    Click one corner of the object's front face, then the opposite corner, exactly like the two corners of a bounding box.
  </Step>

  <Step title="One click for depth">
    Move toward the object's receding direction; the preview extends the depth edges. Click to set the depth point.
  </Step>

  <Step title="Enter to finish">
    Enter completes the cuboid, and it joins Object Instances like any other annotation.
  </Step>
</Steps>

<Frame caption="A finished cuboid on a sedan: filled front face, wireframe depth edges following the car's orientation.">
  <img src="https://mintcdn.com/pixldata/R0Tj9ULA6wrnOpOf/images/docs/editor/cuboid-example.jpg?fit=max&auto=format&n=R0Tj9ULA6wrnOpOf&q=85&s=f8591db57936e9f48fff31f40969139b" alt="Orange cuboid annotation on a white sedan in the PixlHub editor showing front face and depth edges" width="380" height="280" data-path="images/docs/editor/cuboid-example.jpg" />
</Frame>

## Getting the geometry right

* **Front face on the visible face.** Put the rectangle on the surface facing the camera (a car's front or rear); the depth edges then follow the body naturally.
* **Depth follows the vanishing direction.** Drag depth along the object's real-world axis, using lane lines, shelf edges or building lines as perspective references.
* **Edit like everything else.** Select the cuboid and its handles expose both face corners and depth for adjustment; reclassify with a hotkey, delete with Del, undo per operation.

<Frame caption="The cuboid in scene context: perspective encoded that a flat box cannot express.">
  <img src="https://mintcdn.com/pixldata/R0Tj9ULA6wrnOpOf/images/docs/editor/cuboid-context.jpg?fit=max&auto=format&n=R0Tj9ULA6wrnOpOf&q=85&s=2f2cfc096b22fd22cb2b835b6ddb2164" alt="PixlHub editor with a cuboid annotation on a sedan in a busy street scene" width="1152" height="824" data-path="images/docs/editor/cuboid-context.jpg" />
</Frame>

## When cuboid beats box

| Situation                                                | Reason                                                           |
| -------------------------------------------------------- | ---------------------------------------------------------------- |
| Vehicle orientation matters (parking, traffic direction) | The depth edges encode heading                                   |
| Parcel and box measurement pipelines                     | Three visible dimensions instead of two                          |
| Shelf-depth or furniture placement tasks                 | Perspective is the signal, not noise                             |
| Plain detection with no pose need                        | Skip it, a [bounding box](/guides/basics/bounding-box) is faster |

## Frequently asked questions

<AccordionGroup>
  <Accordion title="Is this real 3D data?">
    It is perspective-annotated 2D: a front face plus a projected depth, in image coordinates. Genuinely metric 3D comes from LiDAR projects, where annotation happens in a point cloud.
  </Accordion>

  <Accordion title="How do cuboids export?">
    With their full geometry (face and depth points), alongside other annotation types; downstream code reads them as eight-point projections. See <a href="/guides/essentials/exports">Exports</a>.
  </Accordion>
</AccordionGroup>

## Next steps

<CardGroup cols={2}>
  <Card title="Bounding Box" icon="square-dashed" href="/guides/basics/bounding-box">
    The flat sibling, for when pose does not matter.
  </Card>

  <Card title="Image annotation editor" icon="image" href="/guides/annotation-modules/image-annotation-tool">
    The full tour of tools and panels.
  </Card>
</CardGroup>
