> ## Documentation Index
> Fetch the complete documentation index at: https://docs.liv.tv/llms.txt
> Use this file to discover all available pages before exploring further.
# What is the Unreal LIV SDK?
The **LIV SDK** for Unreal Engine is a Mixed Reality (MR) toolset that enables VR developers to blend real-world video with virtual environments. It offers a complete solution for **MR capture workflows** with adjustable performance settings and integrates with **Meta's Presence Platform** for advanced features in Unreal Engine **5.4+** through the **Meta Fork**.
## **Key Features**
### **Mixed Reality Capture**
* Creates seamless **real-time MR capture** by blending the player's real-world video with virtual VR environments.
* Supports two capture workflows:
* **Background-only Capture**: Isolates the background layer for compositing.
* **Full Composition**: Combines real and virtual elements into a unified view.
### **Customizable Capture Methods**
Choose from three capture methods that balance **performance**, **transparency**
| Capture Method | Performance | Transparency | Post-Processing | Use Case |
| :----------------------------------------------- | :---------- | :------------- | :-------------- | :-------------------------------------------------------------------------------------------- |
| LivCaptureSingle | Fastest | ❌ | ✅ | Best for performance-critical scenarios where transparency and layering are not required. |
| LivCaptureGlobalClipPlaneNoPostProcess | Moderate | ✅ | ❌ | Use for transparent materials when post-processing effects (ex: bloom) are not needed. |
| LivCaptureGlobalClipPlanePostProcess | Slower | ✅ | ✅ | Use when full transparency and post-processing effects (ex: reflections, bloom) are required. |
| LivCaptureBackgroundTransparency (WIP don't use) | Moderate | ✅ (Background) | ❌ | Captures only the background layer with transparency. The player remains excluded. |
| LivCaptureMulti (WIP don't use) | Moderate | ✅ | ✅ | Use for multi-layer captures where both transparency and post-processing are needed. |
### **Meta Presence Platform Integration (Unreal Engine 5.4+)**
When using Unreal Engine **5.4 or later**, the LIV SDK connects with Meta's Presence Platform via the **Meta Fork** to deliver these advanced Mixed Reality features:
* **Passthrough**: Seamlessly blend the real environment with virtual content in real-time.
* **Spatial Anchors**: Lock virtual objects to specific points in the real world.
* **Scene API**: Harness real-world spatial data to create dynamic MR experiences.
Note: Meta Presence Platform features are only available when using the Meta Fork of Unreal Engine, or the Stock Engine + MetaXR plugin.
### **Device and Platform Compatibility**
**Supported Unreal Engine Versions**
| Version | Supported Features |
| :---------------------------------------------- | :------------------------------------------------------ |
| 4.26 to 5.4 | MR capture for Green Screen and immersive workflows. |
| 5.4+ (Meta Fork & Stock Engine + MetaXR plugin) | Supports Meta Presence Platform (Passthrough, Anchors). |
**Platform Requirements**
* **DirectX 11**: Required for all LIV functionality.
* **Note**: DirectX 12 is **not supported**. Use DirectX 11 via Unreal's Project Settings.
* **Windows OS**: Supported for development and deployment.
**Hardware Requirements**
* **VR Headsets**: SteamVR-compatible devices for camera tracking (Oculus Quest, HTC Vive, Valve Index, etc)
## **What's Included in the LIV SDK?**
The LIV SDK includes these essential components for Unreal Engine integration:
1. **Core Plugin Files**:
* `LIV.uplugin`: Unreal Engine plugin definition file.
* **Source Folder**: C++ source code for MR functionality.
* **Content Folder**: Essential assets (ex: shaders, configuration files).
2. **Configuration Tools**:
* Settings for **capture methods**, and clipping planes. (Ignore “Transparency” option)
* Compatibility settings for Meta Presence Platform features.
