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Validation In C++

You have two main C++ extension paths.

Option 1: Subclass UEDInteractionConditionValidator​

This is the best option for reusable rules that can be assigned in multiple places.

Example: Require a pawn tag​

#pragma once

#include "CoreMinimal.h"
#include "Validation/EDInteractionConditionValidator.h"
#include "MyRequirePawnTagValidator.generated.h"

UCLASS(BlueprintType, EditInlineNew, DefaultToInstanced)
class UMyRequirePawnTagValidator : public UEDInteractionConditionValidator
{
	GENERATED_BODY()

public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Validation")
	FName RequiredTag = TEXT("CanInteract");

	virtual void ValidateInteraction_Implementation(const FEDInteractionValidationContext& Context, FEDInteractionValidationResult& InOutResult) override;
};
#include "MyRequirePawnTagValidator.h"

#include "GameFramework/Pawn.h"

void UMyRequirePawnTagValidator::ValidateInteraction_Implementation(const FEDInteractionValidationContext& Context, FEDInteractionValidationResult& InOutResult)
{
	Super::ValidateInteraction_Implementation(Context, InOutResult);

	if (!InOutResult.bAllowInteraction)
	{
		return;
	}

	if (!IsValid(Context.InstigatorPawn) || !Context.InstigatorPawn->ActorHasTag(RequiredTag))
	{
		InOutResult.bAllowInteraction = false;
		InOutResult.DenyReason = EEDInteractionDenyReason::SpecialCondition;
		InOutResult.FailureMessage = FText::FromString(TEXT("Missing required pawn tag."));
	}
}

Assign this validator in:

  • GlobalInteractionValidators
  • ValidationRules
  • ValidationRuleClasses for foliage

Option 2: Override the player component hook​

Subclass UEDPlayerInteractionComponent and override:

  • ValidateInteractionSpecialConditions_Implementation(...)

This is useful for centralized rules.

void UMyPlayerInteractionComponent::ValidateInteractionSpecialConditions_Implementation(
	const FEDInteractionValidationContext& Context,
	FEDInteractionValidationResult& InOutResult)
{
	Super::ValidateInteractionSpecialConditions_Implementation(Context, InOutResult);

	if (!InOutResult.bAllowInteraction)
	{
		return;
	}

	if (bDisableAllSpecialInteractions)
	{
		InOutResult.bAllowInteraction = false;
		InOutResult.DenyReason = EEDInteractionDenyReason::SpecialCondition;
		InOutResult.FailureMessage = FText::FromString(TEXT("Interactions are currently disabled."));
	}
}

Choosing between both approaches​

Prefer a validator object when:

  • you want reuse
  • you want designers to assign/tune rules
  • the same rule applies to actors and foliage

Prefer the player component override when:

  • the rule is highly project-specific
  • it depends on player/controller state
  • you want one centralized decision point

Foliage support​

The validation API is not actor-only.

When the target is foliage, FEDInteractionValidationContext includes:

  • bIsFoliageInstance = true
  • FoliageInstanceComponent
  • FoliageInstanceTransform
  • InteractionLocation
  • bHasFoliageData
  • FoliageData

That makes it practical to implement tool checks, progression checks, or harvesting rules for foliage instances.