This tab of Tracking Group editor allows you to define 3D objects that need to be tracking by multiple cameras.


  • Left panel
  • Tracking object: common parameters
  • Tracking object: point
  • Tracking object: rigid body
  • Filter

You have the possibility to track either a single marker or a rigid body (rigid 3D object) using active markers.

Left panel

On the left panel, a list of currently defined 3D objects is displayed. The button allows enabling/disabling the corresponding object. If the object is enabled the circle to the right of its name defines the object status:

  • grey: tracking is off
  • red: tracking is on but the object is not found
  • green: tracking is on and the object pose is tracked

The following actions are available:
Create new object: to add new tracking object click on button.
Delete object: to delete a tracking object button. Make sure that the object you want to delete is selected.

Tracking object: common parameters

Each tracking object has the following properties:

3D Scene node: this parameter defines a node from 3D Scene the position of which will be controlled by Tracking module. In order to add a 3D node you have to drag&drop the node inside the field.

The fields below display the position and rotation of the object that are determined by tracking. By default, tracking data will override all pose data of the corresponding node. However, it can be changed by clicking on the corresponding coordinate.

Before After Animation
tracking affects all 6 parameters tracking affects only y and z position

Hide if lost: determines the visibility of the object if tracking is lost.

Enable filter: enables the prediction filter to compensate for output latency

Custom filter: use this option in case you want to use custom filter parameters and not the ones in Filter tab.
Refer to Filter section of this page for a description of each parameter.

Tracking object: point

This simple tracking object has only one parameter which is the id of led marker.

Tracking object: rigid body

In order to define a rigid body (a 3D object to track) you need to specify a list of active markers attached to it:

Each “rigid body” object must be defined by at least 3 active markers. You then need to specify the id of each marker as well as its position in the world frame.

Other options:
Select by: use ids or tags for target points
Minimum points (*only if Reject bad points is on): the minimal number of model markers needed for pose estimation. If the number of detected markers is lower than this value, the object will be considered as lost.
Error allowed (*only if Reject bad points is on): the maximal reprojection error. If the reconstructed position of the marker is greater than this value, the corresponding marker will not be taken into account for pose estimation.
Reject bad points activates or deactivates the options above.


Display delay: the latency of the output that the filter will try to compensate.
Measurement noise: variance of measurements coming from tracking and 3D reconstruction.
Process noise: variance of the process noise.

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