User Representation Type

HoloMIT SDK provides a modular system to define and control how each user is visually and functionally represented within a session. Whether you use a 3D avatar, webcam feed, or a full volumetric capture pipeline, the SDK offers a flexible framework to register, instantiate, and extend representations at runtime.

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What Is a User Representation Type?

A User Representation Type defines how a user appears in the virtual world and what capabilities they have (e.g., audio, video, interaction). Examples include:

• A 3D avatar
• A 2D webcam
• A full volumetric reconstruction
• A non-visual participant (e.g., spectator)

These representations are identified via UserRepresentationType, which can be built-in or user-defined.

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Built-in Representations

Out-of-the-box, HoloMIT includes predefined types such as:

ID	Display Name	Interactions
AVATAR	3D Avatar	✅
WEBCAM	2D Video	✅
HOLOCAPTURER_DEPTH	HoloCapturer	✅
SPECTATOR	Audio only / No rendering	❌
NONE	No audio / No rendering	❌

You can list them at runtime using:

UserRepresentationType.GetAll();

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Core Components

Representation Type

A strongly typed runtime‑extensible identifier that declares what kind of representation a user is using. Unlike enums, these types can be registered dynamically, discovered at runtime, sorted, and used in tooling and UI generation.

• Each type is a unique ID + display name.
• Custom types can be created via:

UserRepresentationType.CreateAndRegister("MY_REP", "My Custom Representation", true);

Handler Logic

Each representation type is paired with a handler implementing the behavior of that representation:

• Enabling/disabling different GameObjects
• Connecting pipelines
• Applying different logic for local vs. remote users
• Adapting the scene for producers vs. consumers
• Must implement:

public interface IUserRepresentationHandler {
    void Setup(RepresentationSetupContext context);
}

Registry

• All handlers must be registered in:

RepresentationHandlerRegistry.Register(UserRepresentationType, IUserRepresentationHandler);

UI Integration

Every representation can expose UI data such as:

• Icon
• Description
• Display name
• Lobby text

The UI system can automatically populate dropdowns and selection widgets based on registered representation types. But it is optional to implement.

• Associate icons, labels and descriptions via:

RepresentationUIRegistry.Register(UserRepresentationType, icon, suffix, lobbyText, description);

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How to Create a New Representation

Developers can create entirely new representations:

• Custom holograms
• AI‑driven avatars
• Robot proxies
• Minimalistic “ghost” or “invisible” views
• Hybrid mixed‑reality modes
• Third‑party volumetric solutions

1. Create a type:

var myType = UserRepresentationType.CreateAndRegister("MY_CUSTOM", "My Custom", true);

2. Implement handler:

public class MyCustomHandler : IUserRepresentationHandler {
    public void Setup(RepresentationSetupContext context) {
        // Load model, apply materials, modify parameters, etc.
    }
}

3. Register it:

RepresentationHandlerRegistry.Register(myType, new MyCustomHandler());

4. (Optional) Add UI support:

RepresentationUIRegistry.Register(myType, "Icons/MyIcon", " - (Custom)", "CUSTOM USER", "Custom visual representation");

No SDK core changes are needed.

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Runtime Setup Flow

At runtime, when a player joins:

• The system checks the UserRepresentationType
• It calls TryGetHandler(type, out handler)
• If found, the handler receives a RepresentationSetupContext and instantiates the representation

The context includes:

• The player instance
• Whether the user is local or remote
• Whether it's a preview or full setup
• Source type (e.g. webcam, volumetric, etc.)

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Benefits of This System

• 🧩 Modular – Add or replace representations without changing core logic
• ♻️ Extensible – Add custom pipelines, rendering systems, etc.
• 🧠 Consistent – Uses the same flow across built-in and external handlers
• 🎨 UI-ready – UI registry enables dropdowns, previews, tooltips

Tip: If you're building your own capture/rendering pipeline, integrate it by creating a custom handler and registering it with your own UserRepresentationType.

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📄 See Scripting API documentation: User Representation Type