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The Interaction System handles how players:
  • Pick up items
  • Open containers
  • Harvest foliage and resources
  • Trigger custom world interactions (chests, levers, traps, etc.)
UMI uses an UInteractionComponent placed on the Player Controller to centralize all interaction logic. Location:
/Public/InteractionSystem/InteractionComponent.h

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Using UMI with the Interaction System

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What InteractionComponent Does

UInteractionComponent is responsible for:
  • Raycast / shape traces to detect interactable objects
  • Range validation and line-of-sight checks
  • Instant and hold-to-interact actions
  • Tool requirements (e.g., requires pickaxe)
  • Optional interaction animations
  • Foliage interaction support (for foliage-based resources)

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Setup

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Add InteractionComponent to Player Controller

Important: InteractionComponent goes on the Player Controller, not the Character.
Blueprint Setup
  1. Open your Player Controller Blueprint
  2. Add Component → Interaction Component
  3. Configure properties, for example:
  • Trace Distance: 500 (cm)
  • bUseSphereTrace: true
  • SphereTraceRadius: 20
  • bDrawDebugTrace: false
You can expose these as variables if you want per-controller tuning. C++ Setup 
// In PlayerController.h
UPROPERTY(VisibleAnywhere, BlueprintReadOnly)
UInteractionComponent* InteractionComponent;

// In PlayerController.cpp constructor
AMyPlayerController::AMyPlayerController()
{
    InteractionComponent = CreateDefaultSubobject<UInteractionComponent>(TEXT("InteractionComponent"));
    InteractionComponent->TraceDistance = 500.0f;
    InteractionComponent->bUseSphereTrace = true;
    InteractionComponent->SphereTraceRadius = 20.0f;
}

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Best Practices

  • Use sphere traces over pure line traces for friendlier targeting.
  • Always show clear prompts (“Press E to Pick Up”, “Hold E to Harvest”).
  • Enforce range and line-of-sight to avoid weird interactions.
  • Use hold interactions for harvesting and longer actions.
  • Add animations and progress bars for good feedback.
  • Make all important interactions server RPCs.
  • Use tool requirements to gate advanced resources (pickaxe, axe, etc.).
  • Test at different FOVs and distances to ensure comfortable interaction.