Boids algorithm implementaion in Unity

What is Boids algorithm?

Boids algorithm is an algorithm that tries to mimic the behavior and the movement of the bird flocks. It achieves this by using 3 simple rules:

1. Cohesion: All the birds in the flock must move towards the center of mass of the flock
2. Separation: All the birds must move away from the other birds to avoid collision.
3. Alignment: all the birds must steer towards the average heading direction of the flock.

I have added a 4th rule: border avoidance to make the birds fly in a certain area.

In this implementaion, objects tagged Obstacle will be avoided too. They will be involved in the separation rule.

By summing the vectors obtained from these 4 rules, the final movement direction of each bird can be calculated.

You can read the detailed implementaion breakdown in my medium article here.

How to use this project?

1. Clone this repository.
2. Open the project in Unity 2022.3.16 (Other versions are not tested but they might work).
3. Open SampleScene scene in the scenes folder.
4. Press play.

The flock prefab can be found in Prefabs folder. It has some attributes in the component Flock Manager

• Drone Number: The number of drones to be spawned in the flock.
• Drone Prefab: The prefab of the drone to be spawned.
• Flock Radius: The radius of the area the birds are allowed to flay in.
• Chesion Rule Weight: The weight of the cohesion rule in the final direction vector.
• Separation Rule Weight: The weight of the separation rule in the final direction vector.
• Alignment Rule Weight: The weight of the Alignment rule in the final direction vector.
• Border Avoidance Rule Weight: The weight of the border avoidance rule in the final direction vector.

The drone prefab can be found in the Prefab folder. This prefab has some attributes you can change as well in the Drone component:

• Movement Speed: The speed of the drones.
• Nearby Drones Radius: The radius in which the other drones will be considered near and involved in the separation rule calculation.
• Cohesion Rule Threshold: If the distance between the drone and the center of mass is less than the value of this variable, cohesion rule vector will be multiplied by Cohesion Rule Coefficient.
• Cohesion Rule Coefficient: The number to be multiplied with the cohesion vector if the distance between the bird and the center of mass is less than Cohesion Rule Threshold.
• Direction Low Pass Filter Cutoff: To stabilize the direction vector a low pass filter has been used. It's basically a lerp between the current and previous direction vector. This attribute controls the lerp t argument. 0 means current direction vector and 1 means the previous direction vector.

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The drone model used in this project is made be Mateus Schwaab and is downloaded from here.