stride3d/stride · error · ArgumentException

Please add a NavigationComponent to the entity containing…

Error message

Please add a NavigationComponent to the entity containing PlayerController with the correct navigation mesh!

What it means

PlayerController (Stride navigation test script) requires a NavigationComponent on the same entity to receive pathfinding services. During Start(), Entity.Get<NavigationComponent>() returns null, so the script throws this ArgumentException to signal missing scene configuration.

Solutions

Add a NavigationComponent to the same entity as the PlayerController.
Assign a built/valid navigation mesh to that NavigationComponent.
Verify in the scene editor that both components are on one entity before running.
Null-check Navigation in code if you author PlayerController variants dynamically.

Example fix

// before
Entity.Components.Add(new PlayerController()); // no NavigationComponent
// after
Entity.Components.Add(new NavigationComponent { NavigationMesh = myNavMesh });
Entity.Components.Add(new PlayerController());

Defensive patterns

Strategy: validation

Validate before calling

if (Entity.Get<NavigationComponent>() == null)
    throw new InvalidOperationException("Attach a NavigationComponent to the PlayerController entity before running.");

Type guard

bool HasNavigation(Entity e) => e.Get<NavigationComponent>() != null;

Try / catch

try { playerController.Start(); } catch (ArgumentException ex) when (ex.Message.Contains("NavigationComponent")) { Log.Error("Scene misconfigured: add NavigationComponent"); }

Prevention

Always attach NavigationComponent, CharacterComponent and PlayerController to the same entity
Assign a valid built navigation mesh in the component
Validate scene composition in an editor script or unit test before runtime
Keep scene setup scripted/templated to avoid manual mistakes

When it happens

Trigger: Start() is called on an entity that has a PlayerController script but no NavigationComponent attached in the scene editor.

Common situations: Forgetting to add the NavigationComponent in Game Studio; adding it to a different entity than the PlayerController; the navigation mesh not assigned in the NavigationComponent.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/85097cdc2321548c. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.Navigation.Tests/PlayerController.cs:69


        private bool ReachedDestination => waypointIndex >= pathToDestination.Count;

        private Vector3 CurrentWaypoint => waypointIndex < pathToDestination.Count ? pathToDestination[waypointIndex] : Vector3.Zero;

        private MoveResult pendingResult;
        private TaskCompletionSource<MoveResult> taskCompletionSource;

        /// <summary>
        /// Called when the script is first initialized
        /// </summary>
        public override void Start()
        {
            base.Start();

            // Get the navigation component on the same entity as this script
            Navigation = Entity.Get<NavigationComponent>();
            if (Navigation == null) throw new ArgumentException("Please add a NavigationComponent to the entity containing PlayerController with the correct navigation mesh!");

            // Will search for an CharacterComponent within the same entity as this script
            Character = Entity.Get<CharacterComponent>();
            if (Character == null) throw new ArgumentException("Please add a CharacterComponent to the entity containing PlayerController!");
            
            moveDestination = SpawnPosition;
        }

        public void Reset()
        {
            pathToDestination.Clear();
            HaltMovement();
            moveDestination = SpawnPosition;
            Character.Teleport(SpawnPosition);
        }

        public override void Update()
        {

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