Object Tracking

Object tracking is a feature of Ncam Reality that allows the system to track specific markers when they are detected in either the camera bar or the main camera feed. The position of the marker can then be streamed into Unreal Engine 4 as part of the Ncam Livelink data.

Object tracking is activated via the preferences window of the Full UI. The settings can be found on the lower part of the Tracking tab

Enable the "Track Independent Markers" checkbox to turn on object tracking. The settings below have the following effects:

Video Source - Defines whether the pattern should be detected in the Camera bar feed or the Main camera feed

Coordinate system - Defines how the pattern is tracked in 3d space. "World From Marker" is typically used

Marker Side - This tells the system the size of the pattern that is being used. Ensure that this matches exactly the size of the object tracking pattern that is being used

See the Charts section for information on the object tracking patterns available

Configure Unreal Engine as per normal, ensure the "Markers" field is selected as part of the Ncam profile however

Following this, "Ncam Markers" should appear in the livelink list of data sources.

To attach the Marker livelink data to an object in the UE4 scene. Simply select an actor and attach a "Livelink Controller" component to it.

Inside the details panel of the livelink component, set the "Subject Representation" to "NcamMarkers". Below this a "Marker Info" area is shown, enter into this the ID of the marker being used, this is printed on the lower edge of the marker pattern

The transform values below are used to apply local offsets to the position of the tracked object relative to the marker. Be aware that scaling here will override any scaling that is applied at an object level

There are a number of limitations to be aware of when working with object tracking