Simple AI - Boid Flock Movement

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A Simple 2D AI system for Flock Movement of Birds/Fish/ECT

  • Supported Target Platforms
  • Supported Engine Versions


A Simple 2D AI system for Flock Movement of Birds/Fish

Craig Reyonds published a conference paper that described the movements of flocks in a set of 3 simple rules. 

  1. The members of a flock tends towards its center
  2. The flock aligns its rotation
  3. The flock tries to not overcrowd its self

These were refereed to as Cohesion, Alignment and Separation respectively. The goal being to create a realistic looking emergent movement system for birds/fish/cows where each agent, called a boid, makes its own decisions. 

Ahead based Collision Detection

This allows the Boids to swerve to move around an obstacle without bumping into it, giving a natural curve to their movement patterns.

The asset provides the Behavior tree, Actor, and AI Tasks for a developer to get a 2D flock system working instantly.

Youtube Trailer

Technical Details


  • 8 BP including the Boid Actor
  • Commented and easy to understand BPs
  • Behavior Tree and Blackboard
  • Scale-able performance
  • Out of the box customization of Speed, Rotation, Swarm size
  • Ahead based collision avoidance
  • Silky smooth 60fps on swarms of 40+, with the game tread staying below 10ms. Actor driven swarms are always going to be performance heavy, this component tries to mitigate that and give the developer as much control as possible! (Stats collected on an i7-7700HQ)

V1.1 adds

  • An attractor actor that pulls the swarm towards a central point if they are within the radius.
  • A repulser actor that pushes the swarm away.
  • An additional demo level with a fish pond example.

Number of Blueprints: 10

Input: NA

Network Replicated: No * Nothing is stopping a developer from replicating the actors. However I would encourage the them to consider the network performance of replicating this many actors.

Supported Development Platforms: Windows

Supported Target Build Platforms: Windows


Youtube Link

Support Doc Link

Gamasutra Article Link

Marketplace Forum Tread Link



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