Connecting UE4 to Motionbuilder with Live Link

Describes the process for connecting UE4 to Motionbuilder with the Live Link Plugin

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In this how-to, we go through the setup process to connect Unreal Engine 4 (UE4) to Motionbuilder (Mobu) with the Live Link Plugin. Once you have established a connection, you can stream content from Motionbuilder into UE4 in real-time, enabling you to preview your content in UE4 without the need to export and then import your content into the Engine.

For this guide we are using the Blueprint Third Person Template Project and Mobu 2017.

Live Link works with other versions of Mobu and other DDC tools. For more information, please refer to the Live Link Plugin documentation pages.

1 - Project Setup

  1. Inside your UE4 project, from the Menu Bar under Edit, select Plugins.


  2. Under the Animation section, click Enabled for Live Link, then restart the Editor.


    This will enable the Live Link Plugin, which can be used to connect to external Digital Content Creation (DCC) tools. In order for your DCC tool to connect to UE4, you will need to enable the corresponding plugin. In this how-to, we are establishing a connection with Motionbuilder; however, you could connect to Maya or your own tool (provided that tool has an exposed source to Live Link). 

  3. In the Content Browser under the Content > Mannequin > Animations folder, open the ThirdPersonWalk animation.


  4. From the Toolbar, click Export Asset, then select Preview Mesh and choose a save location. 


  5. Enable the Export Preview Mesh option, then click Export to export the animation and mesh.


  6. Download the Motionbuilder Plugin from the GitHub Repository and extract the zip files to your computer.


    After extracting the zip file, you will find folders for different versions of Motionbuilder, as well as the plugin files needed to set up the plugin inside Mobu.

    The latest version of the plugin will work with UE 4.23. Previous UE versions will require version 1.0.

  7. Inside Motionbuilder, under Settings, select Preferences...


  8. Under SDK, click the Add button and point to the extracted folder path and your version of Motionbuilder. 


    Once you see the path in the window, click Ok


  9. On the confirmation window, click Ok, then restart Motionbuilder for the changes to take effect. 


    In the Asset Browser under Devices, you will now see the UE - LiveLink asset. 


    This enables you to define what from your scene you want to stream to UE4. 

  10. Open the ThirdPersonWalk_PreviewMesh exported from UE4, then click Open on the Open Options menu.


    This will import the character mesh and animation into Motionbuilder. 


  11. In the Asset Browser under Elements, drag a Camera into the viewport. 


    Move the camera to any position desired as this will be an alternate camera we can switch to and preview inside UE4. 


    In the next step we will set up the UE - LiveLink asset to define what elements we want to stream over to UE4.

2 - Mobu Live Link Setup

  1. Inside Motionbuilder's Asset Browser, drag the UE - LiveLink asset into the viewport. 


    This will open up the Live Link Connection window, which you can find under the Devices section. 

    Click image for full view.

  2. Click the ... (selector) Button in the Connection Window, and select the Root bone and Camera, then click the Add button. 


    This will add both as Subjects to stream over to UE4. Notice that the Stream Type is automatically detected based on the content that you are attempting to stream. 


    • Subject Name is the name it will appears as in UE4.

    • Stream Type is what sort of data gets sent.

    • Status is whether or not the Subject is active for streaming.

    With Stream Type, this will be automatically detected based on the type of content you are streaming. However, you can choose the stream type and you may see different options based on your content. 

    Some examples include: 

    Stream Type


    Root Only

    Will only stream the Root Transform.

    Full Hierarchy

    Will grab everything that is a child of the Subject and stream the Transform and whatever animatable properties it has.

    Skeleton Hierarchy

    Streams all child bones of the Subject and checks that they are actually bones (things parented under bones that aren't bones will be ignored).


    Similar to Root Only, except this streams in Camera Properties (for example, Filmback Settings).

  3. In Subject Name field for the Root object, change the name from Root to Character.


  4. Click the button next to Online to enable content streaming. 


    The Online status button will change from Red (Offline) to Green (Online). 

  5. In the Navigator window, under System, enable the Always refresh viewer option. 


    When you are streaming content with Live Link, you will want to enable this option because when Motionbuilder becomes the background application, losing focus, it will throttle performance, which could lead to stuttering during the streaming process.

3 - Streaming Content to UE4

  1. With Mobu running in the background, inside UE4 from the File Menu under Window, select Live Link


    This will open the Live Link Streaming Manager, which will enable you to connect to the running instance of Motionbuilder. 

  2. Click the + Source button, then under Message Bus Source, select your instance of Mobu and click Ok


    The Streaming Manager will update to show the connected Source Type and Subjects being streamed to UE4. 


    Refer to the Live Link Overview page for more information on Live Link options, Roles and Status Indicators.

  3. In the Content Browser under Content > Mannequin > Character > Mesh, open the SK_Mannequin asset. 


  4. On the Preview Scene Settings tab, use the following settings: 


    • Preview Controller: Live Link Preview Controller

    • Subject Name: Character

    • Enable Camera Sync: Enabled

    This enables us to take the Subject named Character in Mobu and stream it in to UE4, previewing it with the Live Link Controller. We are also streaming in the active camera from Mobu.

You can alternatively use Blueprint functions to establish a connection instead of manually connecting through the Live Link UI window. Additionally, instead of using a Preview Controller, you can use a Live Link Component attached to an Actor.

4 - End Result

With both Motionbuilder and UE4 up and connected with Live Link, you can now preview content from Mobu inside UE4 in real-time. In the video below, we are able to manipulate the camera in Mobu and it is reflected inside UE4, we are also able to change camera perspectives and it is updated as well. Scrubbing animations in Mobu is reflected in UE4 and we can adjust bone transforms or keyframe new poses and see those reflected as well. 

You can also directly control Bones in Mobu and see the changes reflected in UE4. This gives you the ability to keyframe animations in Mobu while previewing what those keyframed animations will look like in UE4 in real-time. 

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