unity-ecs-patterns

Convert MonoBehaviours to ECS by creating an authoring component with a nested Baker class that calls AddComponent to attach IComponentData structs to the baked entity. Use GetEntity with TransformUsageFlags.Dynamic for dynamic objects and DependsOn to declare prefab dependencies.

ISystem is an unmanaged struct-based system that is fully Burst-compatible and offers the highest performance, while SystemBase is a managed class with more flexibility but lower performance. The recommended approach is ISystem with [BurstCompile] attributes on lifecycle methods.

Structural changes like creating or destroying entities cannot happen directly inside jobs; use an EntityCommandBuffer instead. Get the buffer from BeginSimulationEntityCommandBufferSystem.Singleton and use its ParallelWriter with IJobEntity for parallel structural changes.

Yes, through the baking pipeline. Authoring MonoBehaviours with Baker classes convert GameObjects and prefabs into entities at bake time, and systems can later instantiate those baked prefab entities using EntityCommandBuffer.Instantiate.

Burst fails when code uses managed types such as classes, strings, or managed arrays inside compiled jobs or systems. Use only unmanaged blittable types, native collections like NativeArray, and ensure all job structs and system methods carry the [BurstCompile] attribute.

Avoid ECS for small projects, complex one-off behaviors, or UI-heavy logic where entity counts are low and OOP is simpler. ECS pays off mainly when simulating thousands of entities or optimizing CPU-bound logic that benefits from batch processing.