Version: Unity 6 (6000.0)
Language : English
Code and scene reload on entering Play mode
Enter Play mode with domain reload disabled

Configuring how Unity enters Play mode

The ability to test your application by switching from Edit mode to Play mode is one of Unity’s core features. You can use Play mode to 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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.

Play mode is intended to provide a realistic preview of how your application is likely to behave for users. By default Unity performs two significant actions on entering Play mode to ensure your project starts and runs as it would in a build:

  • It reloads the scripting domain to reset the application state. For more information on the implications of disabling domain reload and how to compensate for it in your code, refer to Enter Play mode with domain reload disabled.
  • 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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    . For more information on the implications of disabling scene reload and how to compensate for it in your code, refer to Enter Play mode with scene reload disabled.

These two actions take 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. When you frequently make and preview changes, the cumulative time spent waiting to enter Play mode can significantly slow down your development process.

To prioritize faster development iteration times over accuracy of the Play mode simulation, Unity offers the ability to disable domain reload and scene reload on entering Play mode.

The following diagram provides a high-level overview of the effects of disabling domain reload and scene reload:

The effects of disabling domain reload and scene reload settings
The effects of disabling domain reload and scene reload settings

For more detailed information on the effects of disabling domain and scene reload, refer to Details of disabling domain and scene reload.

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 disable domain reload and/or scene reload on enter Play mode:

  1. Open the Project Settings window (Edit > Project Settings).
  2. Click on the Editor tab.
  3. In the Enter Play Mode Settings section, in the When entering Play Mode dropdown menu, do one of the following:
    • To disable domain reloading but enable scene reloading, select Reload Scene only.
    • To disable scene reloading but enable domain reloading, select Reload Domain only.
    • To disable both domain reloading and scene reloading, select Do not reload Domain or Scene.

Additional resources

Code and scene reload on entering Play mode
Enter Play mode with domain reload disabled