For Unity Developers
From 
Unity to 
three.js with 
Needle Engine
Needle Engine provides tight integration with the Unity Editor, allowing developers and designers to work together in a familiar environment and deliver fast, performant, and lightweight web experiences.
Who is this guide for?
- Unity developers learning web development
- Web developers understanding Needle Engine's Unity integration
- Teams bridging Unity and three.js workflows
Getting Started
Make sure you have Needle Engine installed in Unity: Unity Installation
The Basics
Built on three.js
Needle Engine is a 3D web engine built on three.js, one of the most popular WebGL rendering libraries.
Key concept: In Needle Engine, a gameObject is a three.js Object3D. These terms are interchangeable.
Benefits:
- Full three.js compatibility - use any three.js code or library
- Access to the entire three.js ecosystem
- No learning curve if you already know three.js
How Needle Engine Works
Needle Engine does NOT compile C# code to WebAssembly.
Instead:
- Unity defines scene structure, components, and data
- Export process converts to glTF format
- TypeScript/JavaScript powers runtime behavior
Why? Fast iteration speed and maximum flexibility for web experiences. Read more: Vision • Technical Overview
How to create a new Unity project with Needle Engine? (Video)
Learning Path
This tutorial is split into two focused guides to help you learn efficiently:
1. Working with Unity Integration
Start here to understand how Needle Engine integrates with Unity:
- How the Unity workflow translates to web
- Creating and structuring components
- Understanding glTF export
- Managing web projects and packages
- Editor sync and hot reload
Read: Working with Unity Integration →
What you'll learn:
- Unity Editor workflow with Needle Engine
- Component system and
@serializabledecorator - GameObject/Object3D hierarchy and scene structure
- Type mappings (Unity → three.js)
- glTF export process (what gets exported, what doesn't)
- Web project structure on disk
- Package management (npm vs Unity Package Manager)
- Build tools and framework integration
2. C# to 
TypeScript Translation
Continue here to translate your C# knowledge to TypeScript:
- Value types vs reference types (structs vs objects)
- Vector math without operator overloading
- Time, input, and raycasting APIs
- Debug logging and gizmos
- Common utility methods
Read: C# to TypeScript Translation →
What you'll learn:
- Critical differences in how vectors work (copy vs reference)
- Using method calls instead of operators (
vector.add()notvector +) - Accessing time via
this.context.time - Input polling and event subscription
- Raycasting with and without physics
- Console logging and runtime gizmos
- Platform detection utilities
Quick Reference
Core Type Mappings:
| Unity Type | Needle Engine Type | Notes |
|---|---|---|
MonoBehaviour | Behaviour | Base class for components |
GameObject | Object3D | Same as three.js Object3D |
Transform | Object3D | No separate Transform component |
Time.deltaTime | this.context.time.deltaTime | Access via context |
Input | this.context.input | Access via context |
Physics.Raycast | this.context.physics.raycast() | Access via context |
UnityEvent | EventList | Use @serializable(EventList) |
Color | RGBAColor | Custom type with alpha |
Key Difference
In Unity, position is world space by default. In three.js/Needle Engine, position is local space.
Use worldPosition for world coordinates!
New to TypeScript?
If you're not familiar with TypeScript or JavaScript fundamentals, start here:
Learn the core language concepts:
- Variables (
let,const,var) - Functions and arrow functions
- Objects and classes
- Imports and modules
- How references work in JavaScript
What's Next?
After completing both guides:
- Create Components - Build interactive components
- Lifecycle Methods - Complete lifecycle API reference
- Component Reference - Built-in components
- Scripting Examples - Code examples and patterns
Additional Resources:
- three.js Documentation - Core rendering library
- TypeScript Handbook - Language reference
- Needle Engine Samples - Example projects