# Brush Sphere

**Paintbrush 3D** is a tool used in 3D point cloud annotation that allows annotators to "paint" over specific areas of the 3D space.

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## Use Case

* **Segmentation**: By painting over regions in the 3D point cloud, annotators can label areas of interest more intuitively.
* **Freeform Annotation**: It provides flexibility to annotate irregular shapes or areas that are hard to capture with rigid tools like cuboids or polylines.
* **Efficiency**: Allows for faster labeling of large or complex surfaces within a 3D environment.

The 3D paintbrush is particularly useful for annotating non-rectangular objects like vegetation, terrain, or other organic forms in 3D data.

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## Create Segment

1. Click on the '+' icon of the class from the [class list](https://docs.imerit-prod.io/annotation-tool/drawing-tools/pages/t1P8d2reKe3nZWAkN2Kh#id-3.-class-list).

{% hint style="success" %} <img src="/files/qchq9tcQpS8cX7YBw03I" alt="" data-size="line">  "*i"* icon appears on the [header](https://docs.imerit-prod.io/annotation-tool/drawing-tools/pages/t1P8d2reKe3nZWAkN2Kh#id-1.-header) to aid the user with the controls.
{% endhint %}

<figure><img src="/files/yeRwdQhoUEqQyD691om0" alt=""><figcaption></figcaption></figure>

2. Hover the mouse over the drawing area, and a gray circle will appear - this is the sphere tool which also has the same depth.
3. The points inside the paintbrush will tint to yellow color to provide a clear visual indication that the points will get segmented when the annotation begins
4. To increase/decrease the size of the sphere, hold down CTRL + rotate the mouse wheel
5. To begin annotating, hold the left mouse button and drag over the points, the points that were yellow, will get segmented to the class color immediately

<figure><img src="/files/awlSIlb78vQGfSlxRAAe" alt=""><figcaption></figcaption></figure>

6. Once all points belonging to the class are segmented, the user must right-click to save the annotation. [Annotation details](https://docs.imerit-prod.io/annotation-tool/drawing-tools/pages/t1P8d2reKe3nZWAkN2Kh#id-6.-annotation-detail) pop-up will appear.

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## Delete A Segment

To un-segment points, click on any ‘+’ against a class, hold ALT and hover over points.  The points inside the paintbrush will tint to red to denote that these points will be un-segmented. Keeping the ALT key pressed, left click and drag the mouse.  To save, always do a right-click.

<figure><img src="/files/0k82oxFQ8VGKJi2jhOL7" alt=""><figcaption></figcaption></figure>


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