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UE3 Home > Mobile Home > Mobile System Settings

Mobile System Settings


There are many aspects of the way the engine works on mobile devices, such as which features are available to the materials system, whether fog is enabled, or how shaders are handled, that can be configured or controlled through settings in the config files. This document explains these mobile specific system settings as well as other settings which are not specific to mobile devices, but can be configured differently, or overridden, when the engine is running on a mobile device.


You will find the following settings in the [SystemSettings] category of BaseEngine.ini. These settings are global and affect all platforms so use caution when changing them here. You can override these settings per device. See the Device Specific System Settings section for more info.

Setting Name Default Value Description
MobileFeatureLevel 0 Feature level for expensive mobile features. When set to '1' all expensive mobile features (fog,bump,environment mapping, rim lighting, specular, and texture blending) will be turned off
MobileFog True Toggles fog
MobileSpecular True Toggles specular
MobileBumpOffset True Toggles bump offset mapping
MobileNormalMapping True Toggles normal mapping
MobileEnvMapping True Toggles environment mapping
MobileRimLighting True Toggles rim lighting effects
MobileColorBlending True Toggles color blending
MobileVertexMovement True Toggles vertex movement in vertex shaders
MobileLODBias -0.5 How much to bias all texture mip levels on mobile devices (usually 0 or negative)
MobileBoneCount 75 Mobile skeletal mesh bone limit
MobileBoneWeightCount 2 Limit for number of weights that will influence a skeletal mesh on mobile devices
MobileUsePreprocessedShaders True If true, will load from optimized shaders on device, otherwise will load from the unprocessed "source" shaders
MobileFlashRedForUncachedShaders False Whether to flash the screen red (non-final release only) when a cached shader is not found at runtime
MobileWarmUpPreprocessedShaders True On mobile device, whether to load the shaders at startup or load on demand
MobileCachePreprocessedShaders False Used to create a cache of shaders that were seen during an example run on PC
MobileProfilePreprocessedShaders False Generates profiling information for generated shaders
MobileUseCPreprocessorOnShaders True Whether to slim down generated shader code during cooking
MobileLoadCPreprocessedShaders True Whether to load the generated code from the cooker
MobileSharePixelShaders True Whether to share pixel programs or re-compile per "shader" (vertex & pixel combo)
MobileShareVertexShaders True Whether to share vertex programs or re-compile per "shader" (vertex & pixel combo)
MobileShareShaderPrograms True Whether to share shaders (vertex & pixel) or re-compile for identical shaders
MobileEnableMSAA False Whether mobile antialiasing is enabled
MobileContentScaleFactor 1.0 The default global content scale factor to use on device (largely iOS specific). Reducing this can sometimes improve performance

Texture Group System Settings

There are system wide texture group settings that are also important for mobile. You can read more about texture group settings on the texture settings page.


The [SystemSettingsMobile] category allows you to override non-mobile specific settings on mobile devices. For example, by default post process settings (an engine wide feature) is disabled on mobile devices only by overriding their values in [SystemSettingsMobile]. See BaseEngine.ini for more details.


The [SystemSettingsMobileTextureBias] category is for overriding texture LOD group settings for mobile platforms. See the texture settings page for more information on texture LOD group settings.

Device Specific System Settings

There may be cases where you would like to change settings for one device but not others. This is possible on mobile via the config files. The following is a list of device specific system setting categories:

  • [SystemSettingsIPhone3GS] - Settings that are used when the game is running on IPhone 3GS devices.
  • [SystemSettingsIPhone4] - Settings that are used when the game is running on IPhone 4 devices.
  • [SystemSettingsIPhone4S] - Settings that are used when the game is running on IPhone 4S devices.
  • [SystemSettingsIPodTouch4] - Settings that are used when the game is running on IPod Touch 4 devices.
  • [SystemSettingsIPad] - Settings that are used when the game is running on IPad devices.
  • [SystemSettingsIPad2] - Settings that are used when the game is running on IPad2 devices.
    • Android support is available to full UE3 source licensees. If you are developing a UDK title and wish to explore moving from UDK to UE3 in order to target additional platforms, please contact the sales team at Epic to discuss our competitive terms and licensing options.

Any setting in the [SystemSettings] category (including texture bias settings) can be applied per device by overriding their value in the device specific system settings categories.