UE4 iOS Packaged Game Size

Unreal
Engine 4.9

iOS Game Development

There are a number of things that affect the size of a packaged iOS game, from the content it references to the build configuration you choose.

Target Configuration

One of the biggest changes comes from targeting the Shipping configuration instead of Development, which saves about 31 MB. The Shipping configuration uses higher optimization settings, and removes debugging symbols and much of the logging and profiling code,
resulting in much smaller executable sizes.

Example: TappyChicken

Here are some example numbers from cooking and packaging TappyChicken for iOS in the 4.0.1 branch.

This is listing numbers with an executable that has the symbols stripped.

The overall Shipping IPA is 43.8 MB uncompressed (34.8 MB compressed), which breaks down into:

3.9 MB - Loading screens and icons (about the same compressed)

25.5 MB - Executable (never compressed)

We never compress the executable since it is encrypted when uploaded to the App Store and will not compress at all there.

10.6 MB - Engine content (4.8 MB compressed)

3.7 MB - Game content (0.7 MB compressed)

The executable is never compressed and the icons/screens are already compressed, but the game and engine content compresses quite well.

We will continue to work on reducing the amount and size of required engine content over time, as well as look at optimizing the executable size.

The loading screens and icons are 

.png

 files that you create; you can provide fewer variations (Tappy Chicken has one for all the devices) or use simpler icons to reduce their size further.

Game Content References

The size of game content is entirely in your hands; it ends up very reasonable for a small game like Tappy Chicken but it can easily blow out when you add a bunch of extra content.

It is important to understand that any content referenced in your game will get cooked; some common gotchas are referring to huge otherwise unused textures as the default for a texture sample in a material function or material, or referencing unused content
in an disconnected node or unused variable in your blueprint. These count as referenced even if all of your material instances replace them with something else. You can look in the cooked asset folder and if you spot any unexpected assets, use the Reference
Viewer to track down who refers to it.

Note: If you cook via the Launch button on the toolbar, only the content referenced by your
chosen maps will be cooked, but if you package your project, all of the content in
your game will be cooked, even unreferenced content.

Disabling Slate

Content-only projects have a larger executable since they cannot make any assumptions about which plugins and libraries you are using. You can usually shrink your executable a little bit by switching to C++, and disabling unnecessary plugins and libraries at
compile time (via

EnabledPlugins

 and the 

Project.Build.cs

 and 

Project.Target.cs

 files). However, we have an optimization to remove more than 30 MB of Slate assets in content-only games since they cannot use Slate. If you
make a C++ project that does not use Slate, you can save this space by setting 

bUsesSlate = false

 in the constructor of your 

TargetRules

 class in 

Project.Target.cs

.

Unreal
Engine 4.9

iOS Game Development

There are a number of things that affect the size of a packaged iOS game, from the content it references to the build configuration you choose.

Target Configuration

One of the biggest changes comes from targeting the Shipping configuration instead of Development, which saves about 31 MB. The Shipping configuration uses higher optimization settings, and removes debugging symbols and much of the logging and profiling code,
resulting in much smaller executable sizes.

Example: TappyChicken

Here are some example numbers from cooking and packaging TappyChicken for iOS in the 4.0.1 branch.

This is listing numbers with an executable that has the symbols stripped.

The overall Shipping IPA is 43.8 MB uncompressed (34.8 MB compressed), which breaks down into:

3.9 MB - Loading screens and icons (about the same compressed)

25.5 MB - Executable (never compressed)

We never compress the executable since it is encrypted when uploaded to the App Store and will not compress at all there.

10.6 MB - Engine content (4.8 MB compressed)

3.7 MB - Game content (0.7 MB compressed)

The executable is never compressed and the icons/screens are already compressed, but the game and engine content compresses quite well.

We will continue to work on reducing the amount and size of required engine content over time, as well as look at optimizing the executable size.

The loading screens and icons are 

.png

 files that you create; you can provide fewer variations (Tappy Chicken has one for all the devices) or use simpler icons to reduce their size further.

Game Content References

The size of game content is entirely in your hands; it ends up very reasonable for a small game like Tappy Chicken but it can easily blow out when you add a bunch of extra content.

It is important to understand that any content referenced in your game will get cooked; some common gotchas are referring to huge otherwise unused textures as the default for a texture sample in a material function or material, or referencing unused content
in an disconnected node or unused variable in your blueprint. These count as referenced even if all of your material instances replace them with something else. You can look in the cooked asset folder and if you spot any unexpected assets, use the Reference
Viewer to track down who refers to it.

Note: If you cook via the Launch button on the toolbar, only the content referenced by your
chosen maps will be cooked, but if you package your project, all of the content in
your game will be cooked, even unreferenced content.

Disabling Slate

Content-only projects have a larger executable since they cannot make any assumptions about which plugins and libraries you are using. You can usually shrink your executable a little bit by switching to C++, and disabling unnecessary plugins and libraries at
compile time (via

EnabledPlugins

 and the 

Project.Build.cs

 and 

Project.Target.cs

 files). However, we have an optimization to remove more than 30 MB of Slate assets in content-only games since they cannot use Slate. If you
make a C++ project that does not use Slate, you can save this space by setting 

bUsesSlate = false

 in the constructor of your 

TargetRules

 class in 

Project.Target.cs

.