Unity DOTS Demo Hub

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High-performance Unity DOTS/ECS demonstrations — from basic entity movement to full gameplay loops. Built for learning, interviews, and performance benchmarking.

Unity 2022.3 LTS · Entities 1.3.14 · Unity Physics 1.3.14 · Entities Graphics 1.3.2 · URP 14.0.12

Demos

#	Demo	Core Concepts	Scale	Key Pattern
01	Moving Cubes	IJobEntity, Burst, ECB, boundary wrap	1k–50k	Parallel entity update
02	Bouncing Balls	Unity Physics, PhysicsVelocity, collider baking	100–1k	Physics + reset loop
03	Flocking Agents	Boids, Basic/SpatialHash modes, neighbor sampling	500–10k	Parallel flocking
04	Tower Defense	Wave spawning, targeting, projectiles, win/loss	100–500	Gameplay loop + entity pool
05	Flow Field	BFS gradient, BufferLookup, Burst IJobEntity	100–1k	Grid pathfinding

All scenes are in Assets/Scenes/. Each has an auto-setup script under Assets/Editor/.

Quick Start

1. Install Unity 2022.3.62f3c1 (or compatible 2022.3 LTS).
2. git clone https://github.com/YIMO691/Unity-DOTS-demo.git
3. Open the project root folder with Unity Hub. Wait for Package Manager.
4. Auto-setup scripts run on first open — scenes, materials, and prefabs are created automatically.
5. Open Assets/Scenes/DemoHub.unity for the main menu, or any demo scene directly.
6. Press Play.

SubScene baking is mandatory — authoring GameObjects live inside SubScenes. Wait for baking to finish before entering Play Mode.

Architecture

Every demo follows the same pipeline:

MonoBehaviour Authoring  →  Baker<T>  →  IComponentData  →  ISystem / IJobEntity

Shared infrastructure in Assets/Scripts/Shared/:

File	Purpose
CommonComponents.cs	Shared MoveSpeed and Velocity structs
SpawnerHelper.cs	Disposable ECB wrapper for one-shot spawners
GUIStyleHelper.cs	Factory methods for common GUI styles
DemoHUD.cs / DemoHubUI.cs / DemoBackButton.cs	Runtime UI overlay + menu

Demo04 System Pipeline

TowerSpawn → WaveProgression → EnemySpawn → EnemyMovement → TowerTargeting
    → ProjectileMovement → Damage → Cleanup → BaseHealth → GameState

Entity pooling: enemies pre-spawn and reuse via PooledEnemy tag. All 10 systems exclude pooled entities with .WithNone<PooledEnemy>().

Demo05 Flow Field

BFS propagates from target cell outward through a 40×40 grid. Each cell stores a direction vector toward the target. 200+ agents read the gradient via BufferLookup<FlowFieldCell> in a Burst-compiled IJobEntity — zero per-agent pathfinding cost. Click and drag on the ground to move the target in real time.

Performance

Batchmode (Headless, CPU-Only)

Demo	Entities	Frame Time	GC Alloc
Moving Cubes	1,000	1.22 ms	0 B
Bouncing Balls	200	1.23 ms	0 B
Flocking (Basic)	500	1.25 ms	0 B
Flocking (SpatialHash)	500	1.36 ms	0 B
Tower Defense	5 waves	1.44 ms	0 B

Editor Play Mode (with GPU Rendering)

Demo	Entities	Avg FPS	Frame ms	GC/frame
Moving Cubes	1,009	217	4.60	1.4 KB
Bouncing Balls	219	218	4.59	1.2 KB
Flocking (Basic)	515	212	4.71	1.7 KB
Flocking (SpatialHash)	516	208	4.81	1.4 KB
Tower Defense	64 peak	193	5.19	2.4 KB
Flow Field	211	171	5.84	0.9 KB

GC in Play Mode is Editor/rendering overhead — DOTS ECS code itself produces zero allocation. Full methodology and high-stress configs in Documentation~/Benchmark.md.

Tech Stack

Technology	Role
ECS (Entities 1.3.14)	Data-oriented architecture, chunk-based component storage
C# Job System	Multi-threaded parallel processing
Burst Compiler	Native code generation for Jobs
Unity Physics	DOTS-native collision and dynamics
Entities Graphics	GPU-instanced rendering for ECS entities
SubScene Baking	Authoring-to-entity conversion at edit time
URP	Universal Render Pipeline, Forward+ rendering

Project Structure

Assets/
├── DOTS_DemoAssets/Demo01–05/    Prefabs, materials, setup markers
├── Editor/
│   ├── DemoHubSetup.cs            Hub scene + back button injection
│   ├── Demo01MovingCubesSetup.cs  Auto-create scenes & assets
│   ├── Demo02BouncingBallsSetup.cs
│   ├── Demo03FlockingAgentsSetup.cs
│   ├── Demo04TowerDefenseSetup.cs
│   └── Demo05PathfindingSetup.cs
├── Scenes/Demo01–05 + DemoHub     Main scenes & SubScenes
├── Scripts/
│   ├── Shared/                    CommonComponents, SpawnerHelper, GUIStyleHelper, UI
│   └── DOTS/Demo01–05 + Templates ECS systems, components, authoring
├── Tests/
│   ├── EditMode/                  10 unit tests (components, configs, algorithms)
│   └── PlayMode/                  7 smoke tests + 6 benchmark tests
└── Settings/                      URP pipeline assets

Testing

17 tests — all passing.

# EditMode (headless)
& "<Unity>/Editor/Unity.exe" -batchmode -projectPath . -runTests -testPlatform EditMode -quit

# PlayMode (headless)
& "<Unity>/Editor/Unity.exe" -batchmode -projectPath . -runTests -testPlatform PlayMode -quit

Or use Window > General > Test Runner in the Unity Editor.

Contributing

• Prefer ISystem and IJobEntity. Use [BurstCompile] where the code path allows.
• Use EntityCommandBuffer for structural changes. Use LocalTransform (not legacy Transform).
• Keep components small. Convert authoring data with Baker<T>.
• Verify the target demo runs before opening a PR.

Documentation

Document	Content
CLAUDE.md	AI assistant guidance and architecture reference
CHANGELOG.md	Version history
Documentation~/Benchmark.md	Methodology, batchmode + Play Mode results, high-stress guide
Documentation~/Interview_Guide.md	Interview talking points
Documentation~/LEARNING_CHECKLIST.md	Hands-on learning exercises
Documentation~/DOTS_Performance_Optimization.md	DOTS performance theory (中文)

License

MIT — see LICENSE.