AI Movement

The UUDAT_MoveToLocation async task provides a simplified way to move characters and AI to a destination with completion callbacks.

MoveToLocation

Moves a controller's pawn to the specified location. When movement completes (success or failure), the Completed delegate is called.

MoveToLocation

The node provides:

Completed output pin with bSuccess parameter
Latent execution (runs over multiple frames)

#include "AI/UDAT_MoveToLocation.h"
#include "GameFramework/Controller.h"

void AMyCharacter::MovePlayerToLocation()
{
    UWorld* World = GetWorld();
    AController* Controller = GetController();
    const FVector Destination(100.0f, 200.0f, 300.0f);
    constexpr float AcceptanceRadius = 100.0f;
    constexpr bool bDebugLineTrace = false;

    UUDAT_MoveToLocation* Task = UUDAT_MoveToLocation::MoveToLocation(
        World,
        Controller,
        Destination,
        AcceptanceRadius,
        bDebugLineTrace
    );

    if (Task)
    {
        Task->Completed.AddDynamic(this, &ThisClass::OnMoveCompleted);
    }
}

void AMyCharacter::OnMoveCompleted(bool bSuccess)
{
    if (bSuccess)
    {
        UE_LOG(LogTemp, Log, TEXT("Movement succeeded!"));
    }
    else
    {
        UE_LOG(LogTemp, Warning, TEXT("Movement failed!"));
    }
}

Parameters

Name	Type	Default	Description
`WorldContextObject`	`UObject*`	Required	The world context
`Controller`	`AController*`	Required	The controller to move
`Destination`	`FVector`	Required	Target location
`AcceptanceRadius`	`float`	`100.0f`	Distance from destination considered "arrived"
`bDebugLineTrace`	`bool`	`false`	Show debug line to destination

Delegates

Delegate	Parameters	Description
`Completed`	`bool bSuccess`	Called when movement finishes

Set AcceptanceRadius to a reasonable value. Characters rarely reach the exact destination point, so a small radius prevents the task from running indefinitely.

Stuck Detection

The task includes built-in stuck detection. If the pawn stops making progress toward the destination, the task will fail after a timeout.

Stuck Detection Properties

These can be configured before starting the task:

Property	Type	Default	Description
`StuckCheckInterval`	`float`	`0.5f`	Seconds between stuck checks
`StuckThreshold`	`float`	`10.0f`	Minimum distance to move between checks
`MaxStuckTime`	`float`	`3.0f`	Seconds before declaring stuck

Configuring Stuck Detection (C++)

UUDAT_MoveToLocation* Task = UUDAT_MoveToLocation::MoveToLocation(
    World,
    Controller,
    Destination,
    AcceptanceRadius,
    bDebugLineTrace
);

if (Task)
{
    // Configure stuck detection
    Task->StuckCheckInterval = 0.25f;  // Check more frequently
    Task->StuckThreshold = 5.0f;       // Require less movement
    Task->MaxStuckTime = 5.0f;         // Wait longer before failing

    Task->Completed.AddDynamic(this, &ThisClass::OnMoveCompleted);
}

Use Cases

Simple Movement

// Move to a pickup
UUDAT_MoveToLocation::MoveToLocation(
    GetWorld(),
    GetController(),
    PickupLocation,
    50.0f,
    false
)->Completed.AddDynamic(this, &ThisClass::OnReachedPickup);

Patrol System

void APatrolCharacter::MoveToNextPoint()
{
    CurrentPatrolIndex = (CurrentPatrolIndex + 1) % PatrolPoints.Num();

    UUDAT_MoveToLocation* Task = UUDAT_MoveToLocation::MoveToLocation(
        GetWorld(),
        GetController(),
        PatrolPoints[CurrentPatrolIndex],
        100.0f,
        false
    );

    Task->Completed.AddDynamic(this, &ThisClass::OnPatrolPointReached);
}

void APatrolCharacter::OnPatrolPointReached(bool bSuccess)
{
    // Wait at patrol point, then continue
    FTimerHandle WaitTimer;
    GetWorldTimerManager().SetTimer(
        WaitTimer,
        this,
        &ThisClass::MoveToNextPoint,
        PatrolWaitTime,
        false
    );
}

Debug Visualization

Enable bDebugLineTrace during development to visualize the movement path:

UUDAT_MoveToLocation::MoveToLocation(
    GetWorld(),
    GetController(),
    Destination,
    100.0f,
    true  // Show debug line
);

Failure Conditions

The task fails (bSuccess = false) when:

Controller is invalid - The controller was destroyed or is null
Pawn is invalid - The controller has no pawn
Stuck detection triggered - Pawn stopped making progress
Path blocked - Navigation system cannot find a path
Task cancelled - Manually cancelled via code

Always handle the failure case in your completion callback. Don't assume movement will always succeed.

AI Movement

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