Unreal Engine 5 - Smart Enemy AI Tutorial

Introduction

• Series on creating smart enemy AI in Unreal Engine 5
• Smart enemies react to environment and player actions
• Example behaviors:
  • Hiding behind walls, attacking, and hiding again
  • Teleporting if player gets too close
  • Dodging player’s arrows
  • Healing when health is low
• Utilizing AI tools in Unreal Engine:
  • Behavior Trees
  • Environment Query System (EQS)
  • Perception system
• Part 1: Building a basic Behavior Tree and AI Controller
  • Enemy chases player and attacks

Getting Started

• Using Unreal Engine 5.2 and third-person template
• Added custom sword mesh and animation from Mixamo
• Mixing or retargeting assets available on Patreon

Creating Player and Enemy

1. Creating Folders: Player and Enemy

• Create separate folders for player and multiple enemies

2. Duplicating Character Blueprints

• Duplicate third-person character blueprint for player and enemies
  • Move them to respective folders
  • Modify third-person game mode to use the new player blueprint

3. Setting up the Enemy Base Blueprint

• Duplicate player blueprint to create BP_EnemyBase
  • Remove unwanted components (camera, boom, etc.)
  • Adjust mesh and animation settings
  • Create BP_Player and assign in game mode

Implementing Basic Behavior in Blueprints

Chase Player Function

1. Creating Custom Event: ChasePlayer

• Use AI Move To function targeting player character
  • Set acceptance radius and add delay before repeating

2. Setting up Begin Play

• Call ChasePlayer on Begin Play

3. Adding Navigation Mesh

• Required for AI Move To function, add NavMeshBoundsVolume and scale to cover level

Attack Player Function

1. Creating Custom Event: Attack

• Play attack animation montage

2. Adjusting Animation Blueprint

• Adding functionality to disable leg IK during certain animations

Transitioning to Behavior Trees

Setting up Behavior Tree and Blackboard

1. Creating Files

• Create a new Behavior Tree and Blackboard (e.g., BT_EnemyBase, BP_EnemyBase)

2. Defining Sequence and Selector

• Setting up node types (sequence and selector)
  • Basic node: Move To targeting AttackTarget key

3. Implementing AI Controller

• Create and set up AIC_EnemyBase class
  • Run behavior tree and set Blackboard values in OnPossess event

4. Debugging Behavior Tree

• Demonstrating visual debugging in Behavior Tree editor

Implementing Custom Tasks and Decorators

1. Creating Custom Task: Default Attack

• Use Montage and event dispatcher for attack completion

2. Focus on Target Task

• Ensure AI focuses on player before attacking

3. Clearing Focus

• Ensure AI looks where it is moving when not attacking

Adding and Equipping Weapons

1. Socket Setup

• Add socket to right hand for weapon
  • Preview and adjust weapon position

2. Spawning and Attaching Weapon

• Create weapon blueprint (e.g., sword)
  • Spawn actor and attach in custom event

3. Behavior Tree Integration

• Create task to wield weapon and use decorators to manage state

Conclusion and Next Steps

• Completed part one with basic chase and attack behaviors
• Demonstrated using Behavior Trees and Blueprints for AI logic
• Preview for part two: Adding perception, more complex states, etc.