3D Polyline
  • 16 Apr 2024
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3D Polyline

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Article summary

Overview

Dataloop supports annotators to create polyline annotations in 3D data.

A polyline is a continuous line composed of one or more line segments. In data annotation, it's represented as a series of connected points, where each point is defined by its coordinates (e.g., x, y for 2D spaces, and x, y, z for 3D spaces).

3D Polyline annotations are supported only on the LiDAR Annotation Studio.

Polyline Line Type
  • If the polyline is spline, then the line type is spline in the JSON file output.
  • if the polyline is linear, then the line type is linear in the JSON file output.

Create Annotations Using 3D Polyline

  1. Choose the Polyline annotation tool from the available annotation tools.
  2. On the canvas, locate the starting point and initiate the polyline by left-clicking with the mouse.
  3. Identify the endpoint and left-click with the mouse to define it.
  4. Press Enter to finalize the annotation. The polyline will be generated on the canvas and added to the list of annotations. The starting point of the annotation will be highlighted in green.
  5. Adjust the Line Width as required.

Annotate Spline Polyline Annotations

Spline: It allows annotators to create a curve or line segment that has the characteristics of a spline. Annotators can manipulate control points to shape the curve as needed, creating aesthetically pleasing and precisely defined paths.

  1. Select the Polyline annotation tool from the available annotation tools.
  2. Activate the Spline feature.
  3. On the canvas, locate the starting point and initiate the polyline by left-clicking with the mouse.
  4. Identify the endpoint and left-click with the mouse to define it.
  5. Press Enter to complete the annotation. A curved polyline will be generated on the canvas and added to the list of annotations.
  6. Adjust the Line Width as required.
For Spline Polylines
  • For the spline polylines, a gray color point will be added to define as the center point. Select this point to adjust the polyline as needed.
  • Once you click and move the gray point, it becomes as a new permanent point for the polyline with another two gray dummy points will be added as center points. Refer to the following GIF example for a clear understanding of it.

Switch to the Polyline Spline Feature in the Annotation

You can switch an existing polyline annotation to a spline annotation.

  1. Choose the Polyline annotation tool from the available annotation tools.
  2. Enable Spline feature. The normal polyline annotation will be converted to spline polyline annotation.