Unreal Engine 5 Modular Interaction System

A performant, server-validated C++ interaction system for Unreal Engine 5. Designed for decoupled logic, easy Blueprint extension, and safe actor lifecycle management.

Demo_Map.mp4

Key Features

• Optimized Tracing: Uses FTimerHandle instead of Event Tick for local controller line tracing.
• Network Authority: Client-side prediction with server-side distance validation (ServerTryInteract) prevents interaction exploits.
• Safe Lifecycle Handling: Automatically nullifies interaction pointers if the target actor is destroyed (e.g., consumable pickups).
• Blueprint Ready: Interaction logic and UI text are exposed via BlueprintNativeEvent, allowing non-programmers to create interactable objects.

Replication_review.mp4

Demo Map Included

The project includes a ready-to-play map demonstrating three core interaction paradigms:

1. C++ Implementation (Door): A C++ actor using a USceneComponent hinge to manage open/close state.
2. Blueprint Implementation (Light): A fully Blueprint-implemented actor demonstrating interface inheritance without C++ logic.
3. Actor Lifecycle (Pickup): A C++ item that broadcasts its data and calls Destroy() upon interaction, showcasing safe pointer cleanup.

Easy Blueprint Extension

The interaction system is fully decoupled and exposed to Blueprints via IInteractableInterface. Designers and non-programmers can easily create new interactable objects and custom logic without writing a single line of C++ code.

For example, here is the complete implementation of BP_LightSwitch using Event Interact:

Core Architecture

• UInteractorComponent: The brain of the system. Attach to any Pawn/Character. Configurable trace distance (default: 450.f) and timer intervals.
• IInteractableInterface: Requires targets to implement Interact() and GetInteractText() const.

Quick Setup

1. Clone the repository and open .uproject.
2. Ensure your project uses the Interactable Collision Channel (default response: Ignore, block on target actors).
3. Open the included Demo Map to test BP and C++ interactable examples.