# LiveLink plugin

Setting up Live Link for AR 51 in Unreal Engine.

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This document provides a step-by-step guide to setting up Live Link for AR 51 in Unreal Engine. 

<YouTube id="blezarzx5Zg" title="AR 51 Unreal SDK — LiveLink" />

## Prerequisites

Ensure Unreal Engine is installed.

Confirm that AR 51 SDK and Live Link plugins are available and activated.

## Download and Install the Plugins

## Download the Plugins

1. Go to the **[AR 51 Downloads page](/download)**. 

2. Download the **”AR 51 Unreal SDK”** plugin. 

3. Download the **'AR 51 SDK_Live Link'** plugin.

![LiveLink plugin — Download live link](./img/live_link_unreal/1.download_live_link.png)

## Install the Plugin

**Project-Specific Installation:**

1. Navigate to your Unreal Engine project's root directory.

2. If a **Plugins** folder does not exist, create one.

3. Extract the content of the downloaded plugins into the Plugins folder.

:::warning
**Engine-Wide Installation:**

1. Navigate to the Unreal Engine installation directory (e.g., **"C:\Program Files\Epic Games\UE_X.YY\Engine\Plugins\Marketplace\"**).

2.  Extract the content of the downloaded plugins into this folder. 

    Note: Plugins installed here will be available for all projects using this Unreal Engine version.

:::

![LiveLink plugin — UE plugins folder](./img/live_link_unreal/2.UE_plugins_folder.png)

## Activating the Plugins

1. Open Unreal Engine and your project.

2. Go to **Edit > Plugins**.

3. In the Plugins window, use the search bar to find **'Live Link'** and **'AR 51 SDK_Live Link.'**

4. Ensure both **AR 51 SDK_Live Link** and **AR 51 SDK** are enabled by checking their respective boxes.

![LiveLink plugin — UE plugins window](./img/live_link_unreal/3.UE_plugins_window.png)

## Opening Virtual Production

1. Go to the top menu and select **Window**.

2. Choose **Virtual Production** and then **Live Link**.

![LiveLink plugin — Virtual production live link](./img/live_link_unreal/4.virtual_production_live_link.webp)

## Adding AR 51 Live Link Source

1. In the Live Link panel, click **Add Source**.

2. Select **AR 51 Live Link** from the list.

![LiveLink plugin — Live link panel add source](./img/live_link_unreal/5.live_link_panel_add_source.png)

3. The source type should appear as **AR 51 Live Link** and will appear with the status: **Not Connected**.

![LiveLink plugin — Source type not connected](./img/live_link_unreal/6.source_type_not_connected.png)

## Adding Virtual Subject

1. Click **Add Source** again in the Live Link panel.

2. Select **Add Virtual Subject**.

3. Provide a name for your subject (e.g. AR51VirtualSubject).

4. Under the options, select **AR51LiveLinkSubject**.

5. Click **Add**.

![LiveLink plugin — Create virtual subject](./img/live_link_unreal/7.create_virtual_subject.png)

## Creating a Live-Link Character using the Animation Blueprint

## Creating and Setting Up Blueprint

1. In the Content Browser, go to **Plugins > AR 51 SDK Content > Models > Unreal Default Character > Mesh**.

2. Locate the **SK_Mannequin skeletal mesh**.

3. Right-click on it, select **Create**, and then choose **Anim Blueprint**.

4. Name the new blueprint **AR 51 SDK Live Link Character**.

5. Move this blueprint to your project's Content folder.

![LiveLink plugin — Create anim blueprint](./img/live_link_unreal/8.create_anim_blueprint.webp)

## Configuring the Blueprint

1. Open the newly created blueprint.

2. In the blueprint editor, right-click on an empty space and search for **Live Link Pose**.

3. Add the **Live Link Pose** node.

4. Connect the **Input Pose** to the **Result Pose**.

5. In the **Live Link Subject Name** field, select **AR 51 Virtual Subject**.

6. Click **Compile** to save the changes.

![LiveLink plugin — Blueprint input pose](./img/live_link_unreal/9.blueprint_input_pose.webp)

## Testing the Setup

## Drag **AR 51 SDK Live Link Character** into the level

1. Drag and drop the **AR 51 SDK Live Link Character** blueprint into your level.

2. Reset its location to (0,0,0) to center it.

## Drag **AR 51 SDK** into the level

1. Drag and drop the **AR 51 SDK** blueprint into your level.

2. Reset its location to (0,0,0) to center it.

## Play and Examine the Live-Link connection.

1. Press **Play** to start the scene.

2. Open the Live Link panel from **Window > Virtual Production > Live Link** if it's minimized.

3. Ensure that **AR 51 Live Link** in the subject name list shows as connected.

4. In the right-side attributes panel, ensure **Show Model** is enabled under **General**.

![LiveLink plugin — Live link show model](./img/live_link_unreal/10.live_link_show_model.png)

## Conclusion

You've successfully set up Live Link for AR 51 in Unreal Engine. For any issues, revisit the steps and ensure all settings are correct. Thank you for following this guide.