Unity DOTS: Revolutionizing Game Development

Massive Performance Gains

DOTS leverages the Burst compiler and Entity Component System (ECS) to achieve near-native performance. Traditional Unity games might handle thousands of entities, but DOTS enables millions.

Key Benefits:

✓ 10-100x more entities than GameObject/MonoBehaviour
✓ Optimal cache utilization through data locality
✓ Automatic multithreading with Job System

Entity Component System

DOTS replaces GameObjects with a pure ECS architecture where:

Entities

Lightweight IDs representing game objects

Components

Pure data without behavior

Systems

Process components in efficient batches

This separation enables optimal CPU cache usage and makes your game logic inherently parallelizable.

System: MovementSystem

Position

Velocity

Entity 1

Entity 2

Entity 3

Burst Compiler

The Burst compiler transforms C# jobs into highly optimized native code using LLVM, achieving performance comparable to hand-written C++.

Compilation Pipeline:

1

C# Job Code

Write safe, managed code

2

Burst Compilation

LLVM optimizations applied

3

Native Execution

Near-C++ performance

[BurstCompile]

public struct

MyJob : IJobParallelFor {
  [ReadOnly] public NativeArray<float> input;
  [WriteOnly] public NativeArray<float> output;

  public void Execute(int i) {
    output[i] = input[i] * 2f;
  }
}

Compiles to optimized native code

DOTS Use Cases

Mass Simulation Games

RTS units, crowds, particles, or physics objects that need to scale to thousands or millions of entities.

Procedural Generation

Generate massive worlds or content quickly using parallelized algorithms.

High-Performance VR/AR

Maintain high framerates with complex scenes in demanding XR environments.

Getting Started with DOTS

1. Install DOTS Packages

Unity > Window > Package Manager
Install:
- Entities
- Burst
- Mathematics
- Collections

2. Convert GameObjects (Optional)

Use the ConvertToEntity MonoBehaviour to gradually migrate existing GameObjects to ECS.

public class ConvertMe : MonoBehaviour, IConvertGameObjectToEntity {
    public void Convert(Entity entity, EntityManager dstManager, 
        GameObjectConversionSystem conversionSystem) {
        // Add ECS components here
    }
}

3. Write Your First System

[BurstCompile]
public struct RotationSpeed : IComponentData {
    public float RadiansPerSecond;
}

[BurstCompile]
public class RotationSystem : SystemBase {
    protected override void OnUpdate() {
        float deltaTime = Time.DeltaTime;
        
        Entities.ForEach((ref Rotation rotation, 
            in RotationSpeed speed) => {
            rotation.Value = math.mul(
                math.normalize(rotation.Value),
                quaternion.AxisAngle(
                    math.up(), 
                    speed.RadiansPerSecond * deltaTime));
        }).ScheduleParallel();
    }
}