To transmit rigid body data to UE using VRPN, you drive objects in the UE scene using the rigid body from the motion capture software. First, enable the "VRPN" function in XINGYING, attach reflective markers to the object being tracked, create a rigid body in Live mode, and ensure the software is in play mode.
Open the XINGYING settings interface. Since UE's VRPN processes incoming data in meters, change the data unit to meters in the motion capture settings.
Open the UE software, click on "Edit → Plugins" in the upper left corner to open the plugin settings window, and enter "VRPN" and "Live" in the search box. Check both "LiveLinkVRPN" and "LiveLink, " then restart the UE software.
Click on "Window → LiveLink" and, in the "LiveLink" window, add a "LiveLinkVRPN Source." In the "Connection Settings, " keep the "IPAddress" at its default setting without changing it. The frame rate in "Local Update Rate in Hz" should match the frame rate set in the VR Tracker software. Enter the name of the rigid body created in VR Tracker for "Device." For "Subject Name, " enter the name of the subject. Select "Tracker" for "Type, " then click to add. The topic of the rigid body will be added.
Select the topic of the rigid body, click the "+" next to "Pre Processor, " and in the drop-down menu, choose "Transform Axis Swap." In the drop-down for "Transform Axis Swap," modify the "Fornt Axis," "Right Axis," and "Up Axis" so that the transformation axes in UE coincide with the coordinate system axes calibrated in the VR Tracker software. For instance, if the Y-axis is up in the VR Tracker software, the forward axis is X, the right axis is Z, and the up axis is Y. Therefore, in UE, the forward axis, right axis, and up axis should be set to "X, Z, Y, " respectively.
For the following steps, refer to the previously mentioned "Section XVII, Plugins & SDKs (I) UE Plugin LiveLink Rigid Body Application, " steps 5 to 9.
