Main Page → OptiTrack Unreal Engine 4 Plugin → Unreal Engine: OptiTrack Live Link Plugin
Overview
Get Motive streaming with at least one rigid body. Make sure the Streaming settings are configured correctly, and the rigid body is active under the Assets pane.
You can install the OptiTrack Unreal Engine plugin by putting the plugin files into one of the following directories:
C:\Program Files\Epic Games\[Engine Version]\Engine\Plugins
[Project Directory]\Plugins
Go to Edit → Plugins and enable two of the required plugins. First one is the OptiTrack - Live Link plugin under Installed group, and the second one is the built-in Live Link plugin under Built-In group.
Open the LiveLink pane from Window → Live Link in the toolbar.
In the LiveLink pane under Source options, go to the OptiTrack Source menu and configure the proper connection settings and click Create. Please make sure to use matching network settings configured from the Streaming pane in Motive.
If the streaming settings are correct and the connection to Motive server is successful, the plugin will list out all of the detected rigid bodies, and they should have green dots next to them indicating that the corresponding rigid body has been created and is receiving data. If the dots are yellow, it means that the client has stopped receiving data. Check if Motive is still tracking or if there is a connection error.
Add a camera actor from the Place Actors pane or a static mesh from the project into your scene. For the static meshes, make sure their Mobility setting is set to Movable under the Transform properties.
Select an actor you want to animate, click the “Add Component” button on the details pane, and add Live Link Controller.
Under the Live Link Controller component properties → Subject Representation, select the target rigid body.
Once the target rigid body is selected, each object with the Live Link Controller component attached and configured will be animated in the scene.
When the camera system is synchronized to another master sync device and a timecode signal is feeding into eSync, then the received timecode can be used in UE project through the plugin.
From Edit → Project Settings, search timecode and under Engine - General settings, you should find settings for the timecode. Here, set the the Timecode Provider to LiveLinkTimeCodeProvider.
Open the Live Link pane, and select the OptiTrack subject that we created when first setting up the plugin connection. Then, under its properties, check the Timecode Provider box.
The timecode from Motive should now be seen in the Take Recorder pane. Take Recorder pane can be found under Window → Cinematic → Take Recorder in the toolbar.
Right click the mesh you would like to use and select "Create > Anim Blueprint"
Name the animation blueprint something reasonable, then double click it to open the blueprint.
Create a "Live Link Pose" component and connect it to the "Output Pose". Assign the "Live Link Subject Name" to the skeleton that you would like to use.
Change the "Retarget Asset" property in the Details pane of the blueprint editor to "OptiTrackLiveLinkRetarget"
To animate the skeleton in real time click the Animation Blueprint from earlier. In the Details pane press "+ Add Component > Live Link Skeleton Animation". After you add that component the mesh should start animating.
To animate the skeleton in a game, just press the play button. Adding the "Live Link Skeleton Animation" object is not necessary to animate in play mode.
If the retargeting doesn't match the mesh correctly, then you can create a new OptiTrackLiveLinkRetarget blueprint from scratch and modify the bone mapping names.
For testing the project in standalone game mode, or when developing an nDislay application, the Live Link plugin settings must be saved out and selected as the default preset to be loaded onto the project. If this is not done, the configured settings may not get applied. After configuring the LiveLink plugin settings, save out the preset from the Live Link pane first. Then, open the Project Settings and find Live Link section in the sidebar. Here, you can select the default Live Link preset to load onto the project, as shown in the screenshot below. Once the preset is properly saved and loaded, the corresponding plugin settings will be applied to the standalone game mode.
If all the configuration is correct, the actors will get animated in the newly opened game window when playing the project in the standalone game mode.
Q - Trying to add more than 64 frames in the same frame. Oldest frames will be discarded.
A - This notification message may appear at the bottom of the Live Link pane if the frame rate in the data stream doesn't match the rendering frame rate inside UE. This is within notification within the Engine only, so it should not interfere with the project. If this notification must be removed, you can go to the Project Settings → Engine → General Settings → Framerate section, check Use Fixed Frame Rate option, and set the Fixed Frame Rate to be the same rate as the Motive frame rate.
