Difference between revisions of "Active Marker Tracking"

(Tag Setup)
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=See Also=
=See Also=
* [[Active Marker Tracking: IMU Setup]]
* [[Active Puck]]
* [[Active Puck]]
* [[Information for Assembling the Active Tags]]
* [[Information for Assembling the Active Tags]]

Latest revision as of 16:55, 1 July 2021

Main PageActive Marker Tracking

Page Scope

This page provides instructions on how to set up and use the OptiTrack active marker solution.

Additional Note

  • This guide is for OptiTrack active markers only. Third-party IR LEDs will not work with instructions provided on this page.
  • This solution is supported for Ethernet camera systems (Slim 13E or Prime series cameras) only. USB camera systems are not supported.
  • Motive version 2.0 or above is required.
  • This guide covers active component firmware versions 1.0 and above; this includes all active components that were shipped after September 2017.
  • For active components that were shipped prior to September 2017, please see the compatibility notes page for more information about the firmware compatibility.


The OptiTrack Active Tracking solution allows synchronized tracking of active LED markers using an OptiTrack camera system. The active tracking solution mainly consists of the Base Station and the active markers. The active markers can either be active markers on the Tag and/or markers on the active puck which can act as a single rigid body.

The Base Station connects to the camera system and sends out RF signals to the Tags, or pucks, allowing precise synchronization between camera exposure and illumination of the LEDs. Together, they allow Motive to recognize individual active markers in the software, and with labeled markers, more stable rigid body tracking can be achieved. The active markers will never be mislabeled and unique marker placements are no longer be required for distinguishing multiple rigid bodies.

Hardware Setup[edit]

Required Components[edit]

Name Image

Base Station

  • Sends out radio frequency signals for synchronizing the active markers.
  • Powered via PoE.
  • Must be connected to one of the switches in the camera network.


  • Connects to a USB power source and illuminates the active LEDs.
  • Receives RF signals from the Base Station and correspondingly synchronizes illumination of the connected active LED markers.

Active LEDs

  • Emits 850 nm IR light.
  • 4 active LEDs in each bundle and up to two bundles can be connected to each Tag.
  • (8 Active LEDs (4(LEDs/set) x 2 set) per Tag)
  • Size: 5 mm (T1 ¾) Plastic Package, half angle ±65°, typ. 12 mW/sr at 100mA

Active Pucks

A self-contained trackable object which can provide 6 DoF tracking information for any abritary objecct that it's attached to. Carries a factory installed Active Tag with 8 LEDs and a rechargeable battery with up to 10 hour run time on a single charge. The active pucks can also be attached to hands and feet of a player for rigid body skeleton tracking.

Wiring the Components[edit]

Camera System[edit]

  • Active tracking is supported only with the Ethernet camera system (Prime series or Slime 13E cameras). For instructions on how to set up a camera system see: Hardware Setup.

Base Station[edit]

  • Connects to one of the PoE switches within the camera network.
  • For best performance, place the base station near the center of your tracking space, with unobstructed lines of sight to the areas where your Active Tags will be located during use. Although the wireless signal is capable of traveling through many types of obstructions, there still exists the possibility of reduced range as a result of interference, particularly from metal and other dense materials.
  • Do not place external electromagnetic or radiofrequency devices near the Base Station.
  • When Base Station is working properly, the LED closest to the antenna should blink in green when Motive is running.


Base Station LEDs

Note: Behavior of the LEDs on the base station is subject to be changed.

  • Communication Indicator LED: When the Base Station is successfully sending out the data and communicating with the active pucks, the LED closest to the antenna will blink in green. If this LED lights up in red, it indicates that the base station has failed to establish a connection with Motive.
  • Interference Indicator LED: The middle LED is an indicator for determining whether if there are other signal-traffics on the respective radio channel and PAN ID that might be interfering with the active components. This LED should stay dark in order for the active marker system to work properly. If it flashes in red, consider switching both the channel and PAN ID on all of the active components.
  • Power Indicator LED: The LED located at the corner indicates power for the base station.

Tag Setup[edit]

  • Connect two sets of active markers (4 LEDs in each set) into a Tag.
  • Connect the battery and/or a micro USB cable to power the Tag. The Tag takes 3.3V ~ 5.0V of inputs from the micro USB cable. For powering through the battery, use only the batteries that are supplied by us. To recharge the battery, have the battery connected to the Tag and then connect the micro USB cable.
  • To initialize the Tag, press on the power switch once. Be careful not to hold down on the power switch for more than a second, because it will trigger to start the device in the firmware update (DFU) mode. If it initializes in the DFU mode, which is indicated by two orange LEDs, just power off and restart the Tag. To power off the Tag, hold down on the power switch until the status LEDs go dark.
  • Once powered, you should be able to see the illumination of IR LEDs from the 2D reference camera view.
  • Base station setup.
  • Assembled Tags

Puck Setup[edit]

  • Press the power button for 1~2 seconds and release. The top-left LED will illuminate in orange while it initializes. Once it initializes the bottom LED will light up green if it has made a successful connection with the base station. Then the top-left LED will start blinking in green indicating that the sync packets are being received.
  • For more information, please read through the Active Puck page.
  • Puck initializing. Top-left: Orange.
  • Connected to base station and receiving sync packets

Motive Settings[edit]

For tracking active markers in Motive, make sure the below settings are configured in Motive.

Application Settings[edit]

Active marker tracking configuration.

In order for Motive to reconstruct 3D points from the active LEDs, the following setting must be configured under the reconstruction settings:

  • Marker Labeling Mode: Active Markers OR Active and Passive Markers
  • Utilize Active Labels: True

Marker Labeling Mode[edit]

(Default: Passive) The Marker Labeling Mode setting determines whether the point cloud engine reconstructs passive markers, active markers, or both passive and active markers. When Motive is configured to one of the active marker tracking modes, it will be indicated on the perspective view pane.


Calibration Wanding:

When performing calibration wanding, please configure this to the default Passive Markers Only setting. There are known problems with wanding in one of the active marker labeling modes. This applies for both passive marker calibration wands and IR LED wands.

PerspectiveView Active 20.png

Utilize Active Labels[edit]

(Default: True) This should be set to true for stable active marker tracking. When enabled, the point cloud engine uses only the active marker centroids that have the matching active IDs to create a reconstruction. Even if the tracking rays intersect within the allowable residual offset, any centroids with mismatching IDs will be rejected and will not contribute to the reconstruction.

Active Patten Depth[edit]

(Default: 12) This setting sets the complexity of the active illumination patterns. When tracking a high number of rigid body, this may need to be increased to allow for more combinations of the illumination patterns on each marker. When this value is set too low, duplicate active IDs will be produced. In most applications, the default value can be used.

Active Marker Color[edit]

(Default: white) This setting is located under the view tab in the Application Settings pane. The color assigned to this setting will be used to indicate actively labeled markers in Motive.

Camera Settings[edit]

For tracking of the active LED markers, the following camera settings may need to be adjusted for best tracking results:

Camera Exposure[edit]

For tracking the active markers, set the camera exposures a bit higher compared to when tracking passive markers. This allows the cameras to better detect the active markers. The optimal value will vary depending on the camera system setups, but in general, you would want to set the camera exposure between 400 ~ 750, microseconds.

IR LEDs[edit]

When tracking only active markers, the cameras do not need to emit IR lights. In this case, you can disable the IR settings in the Devices pane.
ActiveMarker CameraSettings.png

Active Markers in Motive[edit]

Active Labels[edit]

Unique marker IDs (289, 274, 265) assigned to the active markers

Once the above settings have been configured, active markers will be reconstructed and tracked in Motive. From the unique illumination patterns, each active marker gets labeled individually, and a unique marker ID gets assigned to the corresponding reconstruction in Motive. These IDs can be monitored in the Live-reconstruction mode or in the 2D Mode. To check the marker IDs of respective reconstructions, enable the Marker Labels option under the visual aids (Viewport16.png), and the IDs of selected markers will be displayed in the 3D viewport. The marker IDs assigned to active marker reconstructions are unique, and it can be used to point to a specific marker within many reconstructions in the scene.


Rigid body definitions that are created from actively labeled reconstructions will search for specific marker IDs along with the marker placements to track the rigid body. Further explained in the following section.


Duplicate active frame IDs

For the active label to properly work, it is important that each marker has a unique active IDs. When there are more than one markers sharing the same ID, there may be problems when reconstructing those active markers. In this case, the following notification message will show up. If you see this notification, please contact support to change the active IDs on the active markers.
ActiveMarkers DuplicateID.png

Labels in Recorded 3D Data[edit]

Unlabeled Markers[edit]

In recorded 3D data, the labels of the unlabeled active markers will still indicate that it is an active marker. As shown in the image below, there will be Active prefix assigned in addition to the active ID to indicate that it is an active marker. This applies only to individual active markers that are not auto-labeled. Markers that are auto-labeled using a trackable model will be assigned with a respective label.

ActiveMarker LabeledMarkers.png

Auto-labeled Markers[edit]

When a trackable asset (e.g. rigid body) is defined using active markers, it's active ID information gets stored in the asset along with marker positions. When auto-labeling the markers in the space, the trackable asset will additionally search for reconstructions with matching active ID, in addition to the marker arrangements, to auto-label a set of markers. This can add additional guard to the auto-labeler and prevents and mis-labeling errors.

ActiveMarker LabeledMarkers2.png

Rigid Body Definition[edit]

Rigid body definitions created from actively labeled reconstructions will search for respective marker IDs in order to solve the rigid body. This gives a huge benefit because the active markers can be placed in perfectly symmetrical marker arrangements among multiple rigid bodies and not run into labeling swaps. With active markers, only the 3D reconstructions with active IDs stored under the corresponding rigid body definition will contribute to the solve.

Rigid Body Properties[edit]

If a rigid body was created from actively labeled reconstructions, the corresponding Active ID gets saved under the corresponding rigid body properties. In order for the rigid body to be tracked, the reconstructions with matching marker IDs in addition to matching marker placements must be tracked in the volume. If the active ID is set to 0, it means no particular marker ID is given to the rigid body definition and any reconstructions can contribute to the solve.

ActiveTracking ActiveIDs 20.png

See Also[edit]


› Q : Active markers are flickering from both the 3D viewport in Motive.


  • Make sure Motive is set to tracking Active markers under the reconstruction settings. The Marker Labeling Mode must be set to either Active Markers Only or Active and Passive Markers.
  • If flickering occurs on markers of a specific Tag only, try power cycling it. If it tracks fine afterward, the Tag is using v0.8 firmware.