Brush

The brush tool lets annotators paint directly over areas of the 3D point cloud to segment points by class - ideal for irregular, organic, or free-form shapes.

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Use Case

• Segmentation: Paint over regions to label areas of interest more intuitively than rigid tools allow.

• Freeform Annotation: Annotate irregular shapes or areas that are difficult to capture with cuboids or polygones.

• Efficiency: Label large or complex surfaces - vegetation, terrain, organic forms - faster within 3D environments.

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

Start

Click the + icon next to your desired class in the class list to activate the brush tool.

An "i" icon appears on the header to aid the user with the controls.

2

Position the Brush Sphere

Hover the mouse over the drawing area. A gray circle (the brush sphere) appears, sharing the same depth as the point cloud layer beneath it. Points inside the brush tint yellow - a preview of what will be segmented.

3

Resize the Brush Sphere

Hold Ctrl and scroll the mouse wheel to increase or decrease the sphere size.

4

Paint

Hold the left mouse button and drag over the points you want to label. Yellow-tinted points are converted to the class color immediately as you paint.

5

Save

Once all target points are segmented, right-click to save. The annotation details pop-up will appear to confirm class and instance details.

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Editing a Segment

Adding a Segment

To segment (add) points to an existing annotation:

1. Click + against any class, and hover over the points. Points inside the brush tint yellow (if not already segmented).

2. Left-click and drag to further segment points

3. Right-click to save the changes.

Deleting a Segment

To un-segment (remove) points from an existing annotation:

1. Click + against any class, then hold Alt and hover over the annotation. Points inside the brush sphere tint red to indicate they will be removed.

2. While keeping Alt held, left-click and drag to un-segment the red-tinted points.

3. Right-click to save the changes.

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Keyboard shortcuts

Action	Shortcut
Increase / decrease brush size	Ctrl + scroll wheel
Enter erase mode	Hold Alt
Save annotation	Right-click

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Persistent settings

The last used brush sphere size is retained when switching between drawables or returning after a browser refresh.

Paintbrush size survives browser refresh and logout / login.