# Cuboid Grouping

Cuboid Grouping allows users to link multiple cuboids that move together in the real world - maintaining their relative positions throughout a sequence. This is particularly useful when tracking objects that are physically connected or consistently aligned. The grouping helps improve annotation accuracy, ensures spatial consistency, and reduces the need for manual frame-by-frame adjustments. It’s a good and lean feature, enhancing both annotation quality and workflow efficiency without adding complexity.

{% hint style="success" %} <img src="https://3895963154-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTcOUG6rfWxqGM0N4db2P%2Fuploads%2FGOAkLkFFY9H0DEt10649%2Fbold_idea_icon.png?alt=media&#x26;token=5e795075-b5f4-4e03-a9dd-c01069ceac8b" alt="" data-size="line"> Useful when tracking objects that are physically connected or consistently aligned.
{% endhint %}

![](https://content.gitbook.com/content/TcOUG6rfWxqGM0N4db2P/blobs/iuGk3ssmI1clw9Q43ydl/image)

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## Use Case

* Agri-Tech – Tractor with a Towed Implement\
  Grouping ensures the implement maintains a fixed offset behind the tractor across the sequence, saving time and reducing annotation drift.
* Autonomous Driving – Cabin and a Trailer\
  Helps track multi-part vehicles moving together while preserving their orientation and spacing.

## Benefits

* Good: Maintains consistent spatial relationships between grouped cuboids, improving annotation accuracy across frames.
* Lean: Reduces manual alignment work, especially in sequences where linked objects appear across long spans.
* Flexible: Grouping can be applied and ungrouped selectively over any frame range, offering precise control.

## Steps to Use Cuboid Grouping

{% stepper %}
{% step %}

### Multi-select cuboids

Select the cuboids to be grouped by holding down the Ctrl key and multi-selecting each cuboid.
{% endstep %}

{% step %}

### Choose the lead cuboid

Hover over the cuboid that should lead the group, then right-click (contextual click) and choose “Group” from the context menu.

* The grouping feature will confirm the range and prevent selecting a range where both annotations are not present.
  {% endstep %}

{% step %}

### View orthogonal

Click on an individual cuboid within the group to view the orthogonal view.

* These orthogonal views are read-only as long as the cuboid is grouped.
  {% endstep %}

{% step %}

### Ungroup

Navigate to the frame where the grouping should end. Right-click the lead cuboid and select “Ungroup”.

* The ungroup will confirm the range the ungrouping action should be applied to.
  {% endstep %}
  {% endstepper %}

{% hint style="info" %}
Tip: Use grouping to avoid drift and rework when dealing with attached or coordinated objects that stay aligned throughout a sequence.
{% endhint %}