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Revision as of 18:21, 12 December 2017

HMD Tracking Setup

Setup and optimize the motion capture volume as explained in the Getting Started guide or the Hardware Setup documentations. If you plan to install any obstacles (e.g. walls) within the capture volume, make sure they are non-reflective, and place and orient the cameras so that every corner is thoroughly captured by multiple cameras. For typical rigid body tracking, attach the rigid body markers as instructed from the Rigid Body Tracking page.

General Setup Steps

  1. Attach the markers on the HMD
  2. Create a rigid body asset
  3. Calibrate the Pivot Point of the rigid body
  4. Configure the rigid body settings

Marker Attachment

Passive Markers


When attaching retroreflective markers, make sure markers are securely attached and readily captured by the cameras. For attaching the markers, we recommend using our 20 mm wide and 30 mm tall M4 threaded plastic marker bases with Acrylic adhesives, available at the webstore, to attach the markers onto the HMD.


A markered HMD will be defined as a rigid body in Motive. When placing markers, make sure the placement asymmetry is respected in the arrangement within the HMD. Also, the marker arrangements between multiple HMDs must be incongruent. For more details, read about marker placement from the Rigid Body Tracking page.

Active Markers

Attachment & Placement

With the HMD bracket, simply attach the active marker bracket onto an CV1 HMD and use the active markers on it to define a rigid body.


When using the OptiTrack Active Marker Kit, active markers are actively labeled individually from their own unique illumination patterns, and only the matching active markers get contributed to the rigid body solve. The biggest benefit from the individual labeling is that markers can be placed in perfectly symmetrical placements among multiple rigid body assets.

  • Putting the HMD bracket on
  • When detaching the bracket from the HMD, first pull up the two latches behind the bracket and slowly pull it from the top.

Oculus Positional Tracker (Rift sensors)

  • When using an OptiTrack motion capture system to provide a solution for tracking Oculus HMD, avoid connecting its positional tracker, the Rift sensor, to the host PC.
  • When the tracker is connected, IR LEDs on the connected HMD will illuminate, and it could interfere negatively with the IR tracking of the motion capture system.
  • When Oculus tracker is not recognized by the computer, an error message may appear but you should be able to ignore the error message (Critical Error - can't find the sensor) and proceed without the tracker.

Create an HMD Rigid Body

In Motive, select the markers that are attached on the HMD and create a rigid body (Hotkey: CTRL + T) as you would do for other rigid bodies. Once the rigid body is created, select the asset and open the Properties pane. The following settings need to be configured for HMD tracking.

Rigid body properties for the HMD asset.


Deflection setting is the tolerable distance, in millimeters, that a rigid body marker may deviate from its expected position before it is unlabeled and unassociated with the rigid body. The deflection is set to 4 mm by default. For HMD tracking applications, we recommended lowering this value to 3 or 2. This will reduce the amount of computation required for labeling, and overall latency may be reduced.

Tracking Algorithm

Use the ray-based tracking algorithm. The tracking algorithm setting determines which protocol to use for solving the rigid body in Motive. This algorithm is recommended because it allows tracking to be less susceptible to marker occlusions and solves rigid bodies more robustly without introducing trajectory gaps. This is more suitable for tracking the HMDs since even minor occlusions can acutely affect the experience.

Streaming ID

The User Data value for each rigid body is used as an identification number to reference the rigid body in external applications. Log this value for each rigid body (including the HMD(s)) in the scene. This number will be used to associate the assets in the client applications using the plugin devices.

Min Marker Count

This setting may need to be modified when tracking HMDs with passive markers. To prevent the swapping of the rigid body definition, set this setting to 4. When tracking multiple HMDs, there could be limitations to a variety of unique marker arrangements that could be achieved. If this value is set to a lower value, a set of three markers on an HMD may be congruent to another set in a different HMD, and the rigid body definitions may be switched in Motive.

Calibrate Rigid Body Pivot Point

After the rigid body definition have been created for the HMD, the position and orientation of the rigid body pivot point need to be carefully adjusted for HMD tracking:

  • The pivot point is placed on the bridge of the nose; specifically, right at the midpoint between two eyes.
  • Orientation axes of the rigid body should precisely align with the physical HMD component.
  • Uncalibrated HMD rigid body definition. The pivot point is not positioned nor oriented properly.
  • Calibrated HMD rigid body definition.

Using the HMD Calibration Tool (Passive Markers)


Rigid body pivot can be easily calibrated using the HMD Calibration tool. Supported only for Oculus HMD models only. Does not work with GearVR.

Active HMD Clips

HMD Calibration tool is not supported for the active HMD clips. Active HMD clips are shipped with its rigid body definitions so that it can be easily imported onto Motive. Once you receive the rigid body TRA files, import the TRA files, and use the rigid body refinement tools to refine the location of the rigid body markers.

Manually Calibrating the HMD Pivot Point

If, for some reason, you want to manually position the pivot point without using the HMD Calibration feature, follow the instruction on this page: Manually Calibrating the HMD Pivot Point.

Export the Rigid Body


Tip: Once you have the rigid body asset for the HMD configured, you can export the asset into a TRA file for future uses. Importing the TRA file (e.g. CV1.tra) will load the rigid body (HMD) asset and make it available for use; however, the marker placement must remain unchanged in order to re-load previously created rigid bodies.