This page describes how asset packs work in the context of a Unity Android application that uses Play Asset Delivery.
You can configure Unity to generate an Android App Bundle (AAB) that includes your application split into a base module and asset packs:
Alongside the asset packs that Unity generates automatically, you can also create your own custom asset packs. This is useful when you need to control which assets an asset pack contains. Unity adds your custom asset packs to the final AAB. For more information, see Custom asset packs.
资源包具有下载大小限制。为了解决这个问题，Unity 会根据附加资源的大小更改其生成资源包的方式：
install-time 交付模式 (delivery mode) 的资源包中。如果您不创建任何自定义资源包，这意味着设备会在应用程序安装过程中下载资源包，并且当用户首次启动应用程序时，所有资源都可用。install-time delivery mode to the larger asset pack and assigns the fast-follow delivery mode to the smaller one.Important: If either of these asset packs is larger than the size limit that the Google Play Store allows, Unity displays a warning but doesn’t fail the build. Also, Unity checks the sizes of asset packs individually and doesn’t perform size verification for custom asset packs. This means that, if Unity-generated asset packs fit within the Google Play Store limits but their combination with custom asset packs is too large for the Google Play Store, Unity doesn’t display a warning or error.
对于 Unity 自动生成的资源包，Unity 不支持更改交付模式。如果您想更改资源包的交付模式，请使用您的资源创建自定义资源包。
如果要控制特定资源包中包含哪些非代码资源，可以创建自定义资源包。与 Unity 生成的资源包不同，您可以为自定义资源包设置交付模式。如果您创建自定义资源包，请注意 Google Play 应用商店对资源包的大小和数量限制。有关限制的信息，请参阅下载大小限制。
To use custom asset packs with Addressables, you must extend the Addressables functionality. The Play Asset Delivery Addressables sample provides an example of how to do this. For more information, refer to the sample documentation.