Point clouds in the 3D scene

A depth camera reports the distance to points in front of it. The 3D scene renders that data as a colored point set, placed in the scene by the camera’s frame, so you can see what the camera perceives in the same space as the rest of your machine.

Live point clouds

When your machine is online, the scene streams point clouds from your depth cameras and draws each as a set of points at the camera’s frame. Because each point cloud sits at its camera’s frame, a point cloud that appears in the wrong place usually points to a wrong camera frame, not wrong perception.

Vision services can also contribute point-cloud entities, such as the points behind a detection. These render the same way.

Adjust how point clouds display

Open the Settings panel (gear icon) in the 3D scene tab to control point-cloud rendering:

  • Point size and color: set the default size and color the scene draws points at.
  • Enabled cameras: turn each camera’s point cloud on or off, so you can focus on one camera at a time.
  • Vision: enable or disable vision-service point-cloud entities.

Load and compare external point clouds

To inspect a saved capture, drag a .pcd file onto the viewport. The scene loads it as a point cloud you can view alongside your live data, which is useful for comparing a saved SLAM map or scan against the current frame system.

For a full alignment walkthrough, see Verify point cloud alignment.

Link two point clouds with HoverLink

To compare two point clouds that should align, such as a registered scan and a transformed copy, or ground-truth points and predicted points, link them with HoverLink. Hovering a point in one then highlights the matching point in the other, and the hover tooltip shows both points’ positions.

  1. In Build mode, select a point cloud or arrows entity, such as an imported .pcd file.
  2. In the Details panel, under Actions, click Add Relationship and choose HoverLink.
  3. Pick the other entity, and leave Index mapping set to index to match point N in one to point N in the other. The mapping must use index; without it, Add does nothing.
  4. Click Add.

Links work in every mode, and appear under Relationships in the Details panel, where you can remove them. For imported .pcd files, index matches points correctly only between files whose points are in the same order, because the scene reorders each file’s points when it loads them.