For an overview of how to set up streaming from your Vicon software, see:

As described in the above sections, before you can stream data from your Vicon software, you need to set up Live Link in Unreal Engine 4. When you do this, you supply information about the way in which you want to stream data.

The following table describes the settings that you use to do this.

SettingDescription
Vicon Server NameEnter the IP address or host name of the Vicon PC. For information on connecting two routers, see Multi-route connection.
Port Number

Set to 801 or 804:

  • Tracker: Set to 801. Full datastream output, which allows live and playback modes.
  • Evoke: Set to 804. Low latency output, particularly recommended for VR applications.
  • Shogun: Set to 804. Always Live data (because 801 would be MCP Review).
Use PreFetchSelect this option if WiFi performance is poor and multi-route connection is not possible. PreFetch enables the client to pre-request a frame of data, as opposed to the standard datastream mode of Push (which always sends data), reducing the size of latency spikes caused by unstable network connections.

Evoke users: Do not select this option if you're using a version of Evoke that is earlier than 1.1.2.
Is Retimed

If you select this option, subject data can be provided at a different rate from the Vicon system rate, to match that of the engine. It does this via interpolation and forward prediction of samples.

Offset

If Is Retimed is selected, you can specify (in milliseconds) the amount of prediction that the retiming client will use, dependent on latency time from the Vicon server to client application. 0-3 ms is recommended (the default is 0.0).

Before entering a value, note that forward prediction may cause these issues:

  • When used with unstable and unpredictable WiFi connections, it can cause erratic behavior. Ensure your connection is stable.
  • If tracking is not consistent across the volume, it can also cause problems with poor data quality. Ensure tracking is good across the volume.
Log OutputIf selected, log files are produced in .csv format in the <project root>/Saved/Logs folder, enabling you to review the data that is being received.
Subject Filter

If you need to reduce the amount of data sent over the network, select this option to restrict the data passed from the Vicon datastream into Unreal Engine to only the subjects named in this field. Enter one or more subject names, separating multiple names with a comma.

Subjects that are not named in the Subject Filter field do not appear in the Subject List in the LiveLink panel.

Lens role subjects still appear, even if they have been filtered.

Multi-route connection

Multi-route is a data streaming mode that enables you to simultaneously connect two routers (using two different WiFi channels) to create redundancy in the WiFi network. The client uses whichever frame arrives first from either connection.

Multi-route connection is useful for latency-critical applications such as VR. It is the recommended solution for very busy WiFi environments or when routers/access points experience interference. It ensures a robust and low latency stream of Vicon data to the client application.

For busy WiFi environments that experience interference or latency-critical applications, such as VR streaming, multi-route connection can dramatically improve performance.

To use multi-route connection:

  1. In the Vicon Server Name field, enter the IP address of the first adapter on the Vicon machine, followed by a semi-colon, and then the address of the second adapter.
  2. In the Port Number field, enter either 801 (for Tracker) or 804 (Evoke or Shogun).



  3. To check that your connection has been successful, in Unreal Engine 4, on the Window tab, point to Developer Tools and then click Output Log and review the results.