Unity DOTS : Entity [Part-2]

Pratyush — Sat, 24 Jan 2026 12:25:26 +0000

In the "Introduction" we stuck with "Entity → It is an identifier." but there is a lot more to it.

An Entity is more of an ID provider. This ID is given to all the unique components that come under the one Entity.

For example, if there is a GameObject which represents a cube, it will have a Transform, Mesh Filter, Mesh Renderer, Box Collider, etc. These are components in Authoring data format. When they are converted into an Entity, these properties will turn into Runtime data format.

The logic(scripts) that you create to define the behavior of an Entity is totally separate from the Entity's data itself and data belonging to entity will be arranged contiguously in physical memory with respect to their entity type.

This ability to keep data organized and keep logic separate from the Entity allows bulk manipulation and easy access to data, resulting in a huge performance boost.

Baking

NOTE!

Subscene is used to convert the GameObject to entity because Unity's core scene system is incompatible with ECS.

The conversion of a GameObject to an Entity is called Baking. This process takes in Authoring data and converts it into Runtime data, where:

Authoring data is the data of the object in the Unity Editor
Runtime data is the data that ECS processes during runtime

Links:
Unity DOTS : Introduction [Part 1]

Unity DOTS : Introduction [Part 1]

Pratyush — Thu, 22 Jan 2026 09:05:57 +0000

DOTS

DOTS stands for Data Oriented Tech Stack.

This tech stack helps create games using a data-oriented architecture. By doing this, game projects can scale efficiently while remaining highly optimized.

DOTS consists of three components:

Entity Component System
Job System
Burst Compiler

Entity Component System (ECS)

The Entity Component System has three core parts:

Entity → It is an identifier
Component → It holds data of an entity
System → It performs logical operations on the entity's data

Example

There are three entities (Fig 1.1), each containing two components:

Transform rotation
Rotation angle

A system iterates through all entities and updates their Transform component with respect to their Rotation angle component.

Job System

The Job System makes writing multithreaded code easier by providing pre-implemented safety checks that detect race conditions during development. It also manages how jobs are distributed across CPU cores.

By default, Unity code runs on the Main Thread.

The Job System enables the use of multiple threads called Worker Threads.

Key Features

Jobs are assigned to worker threads
A worker thread can steal jobs from another thread if it finishes early and other jobs are waiting
Automatically handles synchronization between worker threads and the main thread

Burst Compiler

The Burst Compiler works with High-Performance C, which is a restricted subset of C# designed for optimization.

It uses LLVM to translate IL into highly optimized machine code tailored for the target CPU.

Links:
Unity DOTS : Entity[Part 2]

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