UE_MassAI

This project utilizes the Unreal Engine Mass AI plugin to simulate a massive horde of zombies.

The goal is to replicate a "World War Z" swarm behavior: zombies relentlessly pursue the player and, if the target is elevated, pile up on top of each other to scale obstacles.

Table of Content

• Getting Started
• Implementation
• Technology
• Credit

Getting Started

1. Open the Unreal Project (UE5.7)
2. Open map Lvl_City (opens automatically on project load)

Configuration

• Zombie spawn: MassSpawner actor value Spawn/Count
• Zombie need to climb: BP_CustomNavLink actor value NbNeededZombieToClimb
• Number of zombie climbing at a time: BP_CustomNavLink actor value MaxZombieClimbing

Implementation

Zombie Behavior

• Zombie pursuit behavior: StateTree
• Zombie death: Character blueprint

Zombie Movement

Relies on the standard NavMesh to ensure realistic pathfinding across the map.
Since Mass Entities are lightweight and do not possess an AIController, they cannot natively interact with standard NavLinks like traditional Actors.

To solve the limitation of Mass AI regarding verticality, I implemented a Custom NavLink system:

The Problem: The NavMesh correctly identifies a bridge between zones (e.g., ground to building roof), but Mass Entities fail to receive the traversal instruction, causing them to get stuck at the base.
The Solution: A CustomNavLink actor bridges this gap. It intercepts the entities stuck at the link's entry point and overrides their behavior to execute the "climbing/piling up" logic manually.

Debug

The project utilizes the Visual Logger for debugging purposees.

• Log Tags used: behavior and ClimbBehavior

Technology

• Unreal Engine 5.7

Credit

Made by: Vincent DEVINE

Special Thanks

• Baptiste RIMETZ