Configuration Files or Config Files provide the initial settings for Unreal Engine (UE). At their most basic level, they contain lists of key-value pairs organized into sections. These files are used to set default values for objects and properties that are loaded upon startup of Unreal Engine for all builds and platforms. Configuration files use the .ini file extension.

Syntax

Configuration files are structured as follows:

[SECTION1]
<KEY1>=<VALUE1>
<KEY2>=<VALUE2>

[SECTION2]
<KEY3>=<VALUE3>

Every config variable must belong to a [SECTION] and consist of a KEY followed by the = symbol. For example, in BaseEngine.ini:

[Core.Log]
LogTemp=warning

The VALUE can be empty in a config variable, so it is possible to have:

[Core.Log]
LogTemp=

Section Names

Section names are alphabetic strings you can set to any value. The config system loads all declarations in configuration files whether a config variable exists in your project code or not.

Modules

Section headings for configurable objects contained in modules use the syntax:

[/Script/ModuleName.ClassName]

where:

• ModuleName: the name of the module containing the configurable object.

• ClassName: the name of the class within the module ModuleName containing the configurable object.

Plugins

Section headings for configurable objects contained in plugins use the syntax:

[/Script/PluginName.ClassName]

where:

• PluginName: the name of the plugin containing the configurable object.

• ClassName: the name of the class within the plugin PluginName containing the configurable object.

Blueprints

Section headings for configurable assets contained in blueprints use the syntax:

[/PathToUAsset/UAssetName.UAssetName_C]

where:

• PathToUAsset: the path to your asset.

• UAssetName: the name of the asset in PathToUAsset containing the configurable object.

Custom Section Names

Any alphabetic string can be used as a custom category name. For example, if you want a category named "MyConfigSection", write

[MyConfigSection]

When you use custom section names, you must manually query the config variables contained in the section. See the Manually Apply Configuration Settings to Variables section for more information.

Comments

Prepend a semicolon ( ; ) to any line to create a comment in your configuration file. This also works for commenting out key-value pairs as opposed to deleting them from a file.

[Core.Log]
; This section can be used in DefaultEngine.ini to override the display level for different log categories, using lines like the following:
; LogTemp=warning

Key-Value Pairs

Configuration keys can represent a variety of different types of information:

• Strings

• Numerics

• Arrays

• Structs

Array

Array structures in configuration files provide a mechanism for you to combine, accumulate, or override information across multiple configuration files in the configuration file hierarchy. For example, you can add multiple entries to a single configuration array object across multiple files in the hierarchy, such as BaseEngine.ini and DefaultEngine.ini in your engine directory, and DefaultEngine.ini in your project directory.

Configuration files support the following array operations:

Name	Operator	Description	Example
Empty	!	Empty the contents of an array. Any value after = is ignored. For clarity, we recommend you put something descriptive after = such as !MyVar=ClearArray.	!MyArray=ClearArray
Append	+	Append the value to the array if it does not yet exist in the array already. Does nothing if the value already exists in the array.	+MyArray=Value
Remove	-	Remove the value from the array. Must be an exact match.	-MyArray=Value
Append Duplicate	.	Append the value to the array, even if the value already exists in the array.	.MyArray=Value

Array Example

MyConfigArray=7
!MyConfigArray=ClearArray
+MyConfigArray=2
+MyConfigArray=3
+MyConfigArray=4
.MyConfigArray=2
-MyConfigArray=4

The lines in this example perform the following operations:

• MyConfigArray=7: remove everything from array then append 7

• !MyConfigArray=ClearArray: clear the array of all entries

• +MyConfigArray=2: append 2 to the array

• +MyConfigArray=3: append 3 to the array

• +MyConfigArray=4: append 4 to the array

• .MyConfigArray=2: append potential duplicate 2 to the array

• -MyConfigArray=4: remove 4 from the array

In the end, MyConfigArray contains [2,3,2].

Structs

Configuration files support changing struct properties in a config object. The syntax for setting a struct is

[/Script/MyModule.MyClass]
MyStruct=(MyStructProperty1=Value1,MyStructProperty2=Value2,...)

Strings

Quotes support the use of specially escaped characters, hexadecimal, and UTF sequences. This is helpful for localization and internationalization. For example, the following section is contained in BaseEngine.ini:

[Internationalization]
; These are the paths for localizing the core engine itself, the localized game content settings are in *Game.ini
+LocalizationPaths=../../../Engine/Content/Localization/Engine
+CultureDisplayNameSubstitutes="ja;\u53f0\u6e7e;\u30c1\u30e3\u30a4\u30cb\u30fc\u30ba\u30bf\u30a4\u30da\u30a4"
+CultureDisplayNameSubstitutes="\u53f0\u6e7e;\u4e2d\u534e\u53f0\u5317"

Configuration Files in Your Project

There are a few important considerations when using configuration files in your project. These include:

• What categories of configuration files does Unreal Engine recognize?

• How do files within the same category interact with one another?

Configuration File Categories

Unreal Engine recognizes several typical "known" categories of configuration files.

General

• Engine

• Game

• Input

• DeviceProfiles

• GameUserSettings

• Scalability

• RuntimeOptions

• InstallBundle

• Hardware

• GameplayTags

Editor-Only

• Editor

• EditorPerProjectUserSettings

• EditorSettings

• EditorKeyBindings

• EditorLayout

Desktop-Only

• Compat

• Lightmass

Configuration File Hierarchy

There can be multiple different configuration files within each category. For example, the Engine directory contains:

• Engine\Config\BaseGame.ini

• Engine\Config\Windows\WindowsGame.ini

These files are part of the Game configuration file category. Each provides an additional layer of customization.

Configuration files within the same category are organized into a hierarchical structure. If there are duplicate key-value pairs among files in the same category, key-value assignments in latter files override those from files earlier in the hierarchy. Configuration files stored in the Engine directory apply to all projects using this Engine distribution. Configuration files located in the <PROJECT_DIRECTORY> apply only to that particular project. Similarly, configuration files located in <PLATFORM> directories apply only to that particular platform.

Category configuration files are loaded in the following order:

1. Engine/Config/Base.ini

2. Engine/Config/Base<CATEGORY>.ini

3. Engine/Config/<PLATFORM>/Base<PLATFORM><CATEGORY>.ini

4. Engine/Platforms/<PLATFORM>/Config/Base<PLATFORM><CATEGORY>.ini

5. <PROJECT_DIRECTORY>/Config/Default<CATEGORY>.ini

6. Engine/Config/<PLATFORM>/<PLATFORM><CATEGORY>.ini

7. Engine/Platforms/<PLATFORM>/Config/<PLATFORM><CATEGORY>.ini

8. <PROJECT_DIRECTORY>/Config/<PLATFORM>/<PLATFORM><CATEGORY>.ini

9. <PROJECT_DIRECTORY>/Platforms/<PLATFORM>/Config/<PLATFORM><CATEGORY>.ini

10. <LOCAL_APP_DATA>/Unreal Engine/Engine/Config/User<CATEGORY>.ini

11. <MY_DOCUMENTS>/Unreal Engine/Engine/Config/User<CATEGORY>.ini

12. <PROJECT_DIRECTORY>/Config/User<CATEGORY>.ini

Hierarchy Example

To illustrate how the hierarchy works, suppose that you have a project named MyExampleProject and in the Engine/Config/BaseEngine.ini configuration file, you have:

[/Script/EngineSettings.GameMapsSettings]
GameDefaultMap=/Engine/Maps/Templates/OpenWorld

Suppose that you have the following config setting in MyExampleProject/Config/DefaultEngine.ini:

[/Script/EngineSettings.GameMapsSettings]
GameDefaultMap=/Game/ThirdPerson/Maps/ThirdPersonMap.ThirdPersonMap

Since the DefaultEngine.ini file in your project directory supersedes the BaseEngine.ini file in your engine directory, the value of GameDefaultMap when your project starts up is /Game/ThirdPerson/Maps/ThirdPersonMap.ThirdPersonMap.

Use Configuration Variables in Code

You can automatically apply config variables to UPROPERTIES and USTRUCTS or manually read them from the config manager.

Apply Configuration Settings to Variables

Automatically

You can define a class to automatically load values from within the config file hierarchy.

Section Format

To automatically load a config setting in your module code, format [Section] as:

[/Script/ModuleName.ClassName]

where

• ModuleName is the name of the module where the class ClassName is defined.

• ClassName is the name of the class where the variable in question is defined.

Steps to Automatically Load Config Variables

Suppose that you have a module named MyGameModule that has a class named AMyConfigActor, and that AMyConfigActor contains a member variable you want to be able to change in configuration files named MyConfigVariable.

1. Configure which config file category to read in the UCLASS declaration. This example uses the Game category:

   UCLASS(config=Game)
   class AMyConfigActor : public UObject

2. Mark any member variable in the class that you want to be configurable as Config:

   UPROPERTY(Config)
   int32 MyConfigVariable;

3. Set the preceding variables anywhere in the hierarchy of your chosen config file category. For example, since this example uses the Game category, the following configuration can be set within DefaultGame.ini in the project directory:

   [/Script/MyGameModule.MyConfigActor]
   MyConfigVariable=3

Your class should look something like this:

UCLASS(config=Game)
class AMyConfigActor : public UObject
{
    GENERATED_BODY()

    UPROPERTY(Config)
    int32 MyConfigVariable;
}

Manually

As previously mentioned, the config system loads all declarations in configuration files whether an actual config variable exists in your C++ code or not. This means that you can query a config variable in any section. For example, say you have the following config in DefaultGame.ini:

[MyCategoryName]
MyVariable=2

You can read this value into any file you want using the following code:

int MyConfigVariable;
GConfig->GetInt(TEXT("MyCategoryName"), TEXT("MyVariable"), MyConfigVariable, GGameIni);

The value of MyConfigVariable in your game code is now 2.

Manual Read Options

There are several options for functions to retrieve a variable as well as the configuration file category to retrieve said variable from.

Functions

The following functions can be found in ConfigCacheIni.h located in Engine/Source/Runtime/Core/Public/Misc.

• GetBool

• GetInt

• GetInt64

• GetFloat

• GetDouble

• GetString

• GetText

• GetArray

Configuration Categories

The configuration category is identified as G<CATEGORY>Ini. For example, the Engine category is referenced as GEngineIni. The values can be found in CoreGlobals.h located in Engine/Source/Runtime/Core/Public.

Edit Configuration Settings

You can change your configuration settings by either:

• Editing configuration values in an appropriate .ini file.

• Editing configuration values exposed in the Project Settings within Unreal Editor.

Save Configuration Settings in Code

You can save your configuration settings from your game code with SaveConfig.

Save Configuration Example

Suppose that you have the same code as in the example in the section Steps to Automatically Load Config Variables:

UCLASS(config=Game)
class AMyConfigActor : public UObject
{
    GENERATED_BODY()

    UPROPERTY(Config)
    int32 MyConfigVariable;
}

Somewhere in your code, suppose that you edit this configurable variable:

AMyConfigActor *Settings = GetMutableDefault<AMyConfigActor>();
Settings->MyConfigVariable = 42;

You can save this new config value to the config file with absolute path PathToConfigFile as:

FString PathToConfigFile;
Settings->SaveConfig(CPF_Config, *PathToConfigFile);

Related Console Commands

You can see the value of any configuration setting with the GetIni console command. This command helps you to view the value of any configuration setting, including settings for platforms other than the one you are currently using. This command only searches loaded configuration files, so if the setting is in a configuration file that is not loaded, your query might fail.

Command

GetIni [Platform@]IniFile:Section Key

The Platform@ argument is optional. If this is not supplied, Platform defaults to the platform you are currently using.

Example

To find the value of the Protocol key in the URL section of the Engine hierarchy on Windows, run:

GetIni Windows@Engine:URL Protocol

Override Configuration from the Command-line

Unreal Engine provides a mechanism by which you can override configuration settings through command-line arguments.

Specific Config File Properties

Command

-ini:<CATEGORY>:[SECTION_1]:<KEY_1>=<VALUE_1>,[SECTION_2]:<KEY_2>=<VALUE_2>,...

Description

Override the specified KEY with the provided VALUE contained in the given SECTION of the configuration file CATEGORY. For a full list of available configuration file categories, see the Configuration File Categories section of this page.

Example

-ini:Engine:[/Script/Engine.Engine]:bSmoothFrameRate=False,[TextureStreaming]:PoolSize=100

Override the value of bSmoothFrameRate contained in the [/Script/Engine.Engine] section of the Engine category hierarchy, no matter the previous value. Same for the PoolSize.

Default File in Category

Command

-Def<CATEGORY>Ini=<FILE_NAME>

Description

Override the Default<CATEGORY>.ini file with the file <FILE_NAME> where CATEGORY is the specific configuration file type you wish to override. For a full list of available configuration file categories, see the Configuration File Categories section of this page.

Example

-DefGameIni=FooGame.ini

FooGame.ini overrides the DefaultGame.ini configuration file. For a full list of available configuration file categories, see the Configuration File Categories section of this page.

All Files in a Category

Command

-<CATEGORY>Ini=<FILE_NAME>

Description

Override all configuration files in the given CATEGORY. For a full list of available configuration file categories, see the Configuration File Categories section of this page.

Example

-EngineIni=FooEngine.ini

FooEngine.ini overrides all other *Engine.ini files. For a full list of available configuration file categories, see the Configuration File Categories section of this page.

Config File with Matching Suffix

Command

-iniFile=<PATH/TO/FILE_NAME>

Description

Override the config file with the matching suffix path.

Example

-iniFile=C:/MyAdditionalConfigFiles/Engine/Config/BaseEngine.ini

C:/MyAdditionalConfigFiles/Engine/Config/BaseEngine.ini overrides the configuration file <PROJECT_DIRECTORY>/Engine/Config/BaseEngine.ini. For a full list of available configuration file categories, see the Configuration File Categories section of this page.

All Config Files

Command

-IniBootstrap=<FILE_NAME>

Description

Override all config files being loaded and parsed. Read-only.

Example

-IniBootstrap=Foo.ini

Foo.ini is the only configuration file loaded, nothing else.

Set Console Variables in Configuration Files

Configuration Files provide another mechanism for specifying console variables. Some console variables can be set in general configuration categories whereas others should be set in specific configuration categories. Generally, console variables are set in the [ConsoleVariables] section in DefaultEngine.ini within your project directory.

Specific Categories

The following table describes the specific categories of console variables that should be set in particular sections:

Type	Section	Description
Rendering	[/Script/Engine.RendererSettings]	Any console variable starting with r.
Rendering Override	[/Script/Engine.RendererOverrideSettings]	Specifically for the console variable r.SupportAllShaderPermutations
Streaming	[/Script/Engine.StreamingSettings]	Any console variable starting with s.
Garbage Collection	[/Script/Engine.GarbageCollectionSettings]	Any console variable starting with gc.
Network Settings	[/Script/Engine.NetworkSettings]	Only for the console variables n.VerifyPeer, p.EnableMultiplayerWorldOriginRebasing, and NetworkEmulationProfiles.
Cooker Settings	[/Script/UnrealEd.CookerSettings]	Any console variable starting with cook.

Useful Source Files for More Information

The following engine files provide more information about the config system and its components:

• ConfigCacheIni

• CoreGlobals

• ConfigHierarchy