unity-ecs-patterns

SKILL.md

Unity ECS Patterns

Production patterns for Unity's Data-Oriented Technology Stack (DOTS) including Entity Component System, Job System, and Burst Compiler.

When to Use This Skill

Building high-performance Unity games

Managing thousands of entities efficiently

Implementing data-oriented game systems

Optimizing CPU-bound game logic

Converting OOP game code to ECS

Using Jobs and Burst for parallelization

Core Concepts

1. ECS vs OOP

Aspect
Traditional OOP
ECS/DOTS

Data layout
Object-oriented
Data-oriented

Memory
Scattered
Contiguous

Processing
Per-object
Batched

Scaling
Poor with count
Linear scaling

Best for
Complex behaviors
Mass simulation

2. DOTS Components

Entity: Lightweight ID (no data)
Component: Pure data (no behavior)
System: Logic that processes components
World: Container for entities
Archetype: Unique combination of components
Chunk: Memory block for same-archetype entities

Detailed patterns and worked examples

Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.

Best Practices

Do's

Use ISystem over SystemBase - Better performance

Burst compile everything - Massive speedup

Batch structural changes - Use ECB

Profile with Profiler - Identify bottlenecks

Use Aspects - Clean component grouping

Don'ts

Don't use managed types - Breaks Burst

Don't structural change in jobs - Use ECB

Don't over-architect - Start simple

Don't ignore chunk utilization - Group similar entities

Don't forget disposal - Native collections leak