Inventory system with array of structs for items

Pattern: Struct S_InventoryItem(ItemName:String, Quantity:int, Icon:Texture2D, bStackable:bool). Variable Inventory(Array<S_InventoryItem>). AddItem: ForEachLoop(Inventory) → Branch(Element.ItemName == NewItem.Name AND bStackable) → True: SET Element.Quantity += Amount. If not found: Array_Add(NewItem). RemoveItem: Find index → Branch(Quantity > 1) → True: decrement. False: Array_Remove.

Inventory: add/remove items with array of structs

Create struct FInventoryItem: {ItemName (Name), ItemCount (int), ItemData (object ref)}. Variable: Inventory (Array<FInventoryItem>). AddItem: ForEachLoop(Inventory) → CastTo/Break FInventoryItem → Branch(ItemName==NewItem.Name) → True: Get → Modify Count → Array Set (replace at index) → return. If not found: Make FInventoryItem → Array Add. RemoveItem: Find by name → Branch(Count>1) → True: decrement → Set at index. Else: Array Remove at index. Key: Arrays of structs require 'Array Set' with index to modify in place — getting and modifying a copy does NOT update the array.

Pickup and collectible system with overlap trigger

Pattern: Pickup actor with SphereCollision(overlap), StaticMesh visual. OnComponentBeginOverlap → CastTo PlayerCharacter → Success: call AddScore/AddItem interface on player → PlaySoundAtLocation → SpawnEmitterAtLocation → DestroyActor(self). Set collision to OverlapOnlyPawn for performance.

Possess — make a Controller possess a Pawn

GetPlayerPawn — get player pawn by index

Array: build dynamic list, iterate, find and remove items

ADD: Array Add (Target Array=MyArray, New Item=newElement). READ: Array Get (Target Array=MyArray, Index=i) → use 'Item' output. FIND: Array Contains (returns bool) or Array Find (returns index, -1 if not found). REMOVE by index: Array Remove (Target Array=MyArray, Index=i). REMOVE by value: Array Remove Item (Target Array=MyArray, Item=value). ITERATE: ForEachLoop(Array=MyArray) → 'Array Element' output is the current item. LENGTH: Array Length (returns int). Key: Array nodes operate on the array BY REFERENCE — always connect the array variable directly.

Create a Blueprint for a health pickup that restores health when overlapped by the player

Asset reference points to a Blueprint that no longer exists

Why: Some node or variable hardcoded a reference to BP_{name}, but that file was deleted or moved. The Asset Registry can't resolve it. Fix: Either: (a) re-create BP_{name} if accidentally deleted (Content Browser → right-click → Blueprint Class), or (b) update the reference to point at the correct existing Blueprint, or (c) make the reference soft (TSoftObjectPtr) so missing assets don't fail compilation.

Performance optimization checklist for Blueprints

1. TICK MANAGEMENT: - Disable tick on static actors (SetActorTickEnabled=false). - Use SetActorTickInterval(0.1-0.5) for AI, non-critical systems. - Prefer event-driven over tick polling where possible. 2. AVOID EVERY-TICK EXPENSIVE CALLS: - GetAllActorsOfClass: cache in BeginPlay, refresh only when needed. - CastTo: cache result in variable after first cast. - GetComponentByClass: call once and store reference. 3. VISIBILITY: - SetActorHiddenInGame + SetActorTickEnabled=false for off-screen actors. - Use LOD (Level of Detail) on meshes. 4. SPAWNING: - Use object pooling for frequently spawned/destroyed actors (bullets, effects). 5. EVENTS OVER POLLING: - Use overlap events instead of periodic distance checks. - Use delegates/dispatchers instead of checking conditions each frame.

GetPlayerCharacter — get player character by index

UGameplayStatics::GetPlayerCharacter.