# Object-oriented development

> Develop Unity projects with the traditional object-oriented programming philosophy and architecture.

Traditional Unity projects are grounded in object-oriented design principles and programming philosophy, which is centered around objects, their properties and functions, and the relations between these objects. Code is organized around [GameObjects](/engine/6000.0/manual/working-with-gameobjects.md) whose behavior is controlled by attached [MonoBehaviour](/engine/6000.0/manual/scripting/object-oriented-development/fundamental-unity-types/class-mono-behaviour.md) [components](/engine/6000.0/manual/working-with-gameobjects/unity-components/components.md). In general, these MonoBehaviour components encapsulate logic (methods) and data (fields) together, which can be convenient but can have performance issues at scale.

An alternative to object-oriented development is data-oriented development, which is both a design philosophy and a set of technologies that help you implement that philosophy. This approach stresses a clear separation between code and data to maximize CPU cache efficiency and parallelism. Instead of MonoBehaviours, the [Entity Component System (ECS)](https://unity.com/ecs) architecture uses components for data, and systems for logic. The data-oriented approach offers strong performance advantages at scale but can be more challenging for inexperienced developers to learn.

Object-oriented and data-oriented development are not mutually exclusive and you can combine elements from both. For information on data-oriented development, refer to [Unity's Data-Oriented Technology Stack](https://unity.com/dots).

| **Topic**                                                                                                                           | **Description**                                                                                                                                                                                 |
| ----------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **[Fundamental Unity types](/engine/6000.0/manual/scripting/object-oriented-development/fundamental-unity-types.md)**               | Understand some of the fundamental C# types that Unity provides and their special significance and behavior in the Unity Editor and runtime.                                                    |
| **[Managing update and execution order](/engine/6000.0/manual/scripting/object-oriented-development/managing-update-order.md)**     | Understand the order in which Unity executes your script components and the lifecycle callbacks within those scripts during the runtime application loop.                                       |
| **[Managing time and frame rate](/engine/6000.0/manual/scripting/object-oriented-development/managing-time-and-frame-rate.md)**     | Understand how Unity measures time so you can manage the rate at which time passes in your application and ensure values update according to the appropriate time scale.                        |
| **[Split tasks across frames with coroutines](/engine/6000.0/manual/scripting/object-oriented-development/coroutines-section.md)**  | Split the execution of a task synchronously across multiple scenes with coroutines. This can be useful for tasks that should progress gradually over several frames, such as a fade out effect. |
| **[Interacting with web servers](/engine/6000.0/manual/scripting/object-oriented-development/web-request.md)**                      | Use the UnityWebRequest system to allow your application to interact with a web server via HTTP.                                                                                                |
| **[Handle type data generically with Unity Properties](/engine/6000.0/manual/scripting/object-oriented-development/properties.md)** | Use the Unity Properties API to generically discover and manipulate object properties at runtime.                                                                                               |
| **[Programming with mathematics](/engine/6000.0/manual/scripting/object-oriented-development/programming-math.md)**                 | Use Unity's mathematical APIs to apply trigonometric, logarithmic, and other functions in your application, move objects with vectors, and generate random values.                              |

## Additional resources

* [Unity's Data-Oriented Technology Stack](https://unity.com/dots)
* [GameObject](/engine/6000.0/manual/working-with-gameobjects/gameobject-fundamentals/class-game-object.md)