Version: Unity 6 (6000.0)
Language : English
Code reload in the Unity Editor
Domain Reloading

Configurable Enter Play Mode

Play mode is one of Unity’s core features. You can use Play mode run your project directly inside the Editor, through the Play button in the ToolbarA row of buttons and basic controls at the top of the Unity Editor that allows you to interact with the Editor in various ways (e.g. scaling, translation). More info
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. When you enter Play mode, your project starts and runs as it would in a build. Any changes you make in the Editor during Play mode reset when you exit Play mode.

When you enter Play mode in the Editor, Unity performs two significant actions to ensure your project starts in the Editor as it would in a build:

  • It resets the scripting state. This is also called a “Domain Reload”.
  • It reloads the sceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
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    .

These two actions can take some time to perform, and the amount of time increases as your scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
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and Scenes become more complex.

The ability to quickly enter and exit Play mode is an important factor while you are developing your game or app. The faster you can enter and exit Play mode, the faster you can make and test changes.

Fast iteration time while developing is important, and because the time to reset the scene and scripting state can become an obstacle to that, Unity offers the ability to configure what happens when you enter Play mode. You have the option to disable the Domain Reload and Scene Reload actions. These options are provided by the Configurable Enter Play Mode feature.

This diagram illustrates the effects of disabling the Reload Domain and Reload Scene settings.

The effects of disabling the Reload Domain and Reload Scene settings
The effects of disabling the Reload Domain and Reload Scene settings

Configure Play mode settings

You can configure what processes start when you enter Play mode in Enter Play Mode Settings in the Editor section of the Project SettingsA broad collection of settings which allow you to configure how Physics, Audio, Networking, Graphics, Input and many other areas of your project behave. More info
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window.

To enter Play mode faster, you can disable domain reloading and scene reloading from the When entering play mode dropdown. You can disable both, one, or neither of these options.

Additional resources

Code reload in the Unity Editor
Domain Reloading