System Settings

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Unreal Engine 4 allows one to control various performance-related features through the FSystemSettings class, which is initialized from the [SystemSettings] section of Engine.ini.

The following sections detail the various settings that can be controlled through [SystemSettings]. The .ini setting is literally the string name of the variable, and the type of the variable determines the values that are supported. See EngineIni[SystemSettings] for an example.

Texture LOD Settings

A great description of the settings for controlling texture resolution and detail can be found in the Texture Support and Settings page.

World Detail Settings

DetailMode

(int32) (1-3) Current detail mode; determines whether components of Actors should be updated/ ticked. Corresponds to the EDetailMode enum in Scene.uc, also set in PrimitiveComponent, and returned by WorldSettings.GetDetailMode().

SpeedTreeLeaves

(bool) Whether to allow rendering of SpeedTree leaves.

SpeedTreeFronds

(bool) Whether to allow rendering of SpeedTree fronds.

StaticDecals

(bool) Whether to allow static decals.

DynamicDecals

(bool) Whether to allow dynamic decals.

UnbatchedDecals

(bool) Whether to allow decals that have not been placed in static draw lists and have dynamic view relevance.

DecalCullDistanceScale

(float) Scale factor for distance culling decals.

DynamicLights

(bool) Whether to allow dynamic lights.

CompositeDynamicLights

(bool) Whether to composte dynamic lights into light environments.

HighQualityLightmaps

(bool) Whether to allow directional lightmaps, which use the material's normal and specular.

MotionBlur

(bool) Whether to allow motion blur.

MotionBlurPause

(bool) Whether to allow motion blur to be paused.

DepthOfField

(bool) Whether to allow depth of field.

AmbientOcclusion

(bool) Whether to allow ambient occlusion.

Bloom

(bool) Whether to allow bloom.

UseHighQualityBloom

(bool) Whether to use high quality bloom or fast versions.

Distortion

(bool) Whether to allow distortion.

FilteredDistortion

(bool) Whether to allow distortion to use bilinear filtering when sampling the scene color during its apply pass.

DropParticleDistortion

(bool) Whether to allow dropping distortion on particles based on WorldSettings::bDropDetail.

LensFlares

(bool) Whether to allow rendering of LensFlares.

FogVolumes

(bool) Whether to allow fog volumes.

OneFrameThreadLag

(bool) Whether to allow the rendering thread to lag one frame behind the game thread.

SkeletalMeshLODBias

(int32) LOD bias for skeletal meshes.

ParticleLODBias

(int32) LOD bias for particle systems.

Fractured Detail Settings

bAllowFracturedDamage

(bool) Whether to allow fractured meshes to take damage.

NumFracturedPartsScale

(float) Scales the game-specific number of fractured physics objects allowed.

FractureDirectSpawnChanceScale

(float) Percent chance of a rigid body spawning after a fractured Static Mesh is damaged directly. [0-1]

FractureRadialSpawnChanceScale

(float) Percent chance of a rigid body spawning after a fractured Static Mesh is damaged by radial blast. [0-1]

FractureCullDistanceScale

(float) Distance scale for whether a fractured Static Mesh should actually fracture when damaged.

Shadow Detail Settings

DynamicShadows

(bool) Whether to allow dynamic shadows.

MinShadowResolution

(int32) min dimensions (in texels) allowed for rendering shadow subject depths.

MaxShadowResolution

(int32) max square dimensions (in texels) allowed for rendering shadow subject depths.

ShadowTexelsPerPixel

(float) The ratio of subject pixels to shadow texels.

ShadowDepthBias

(float) Depth bias that is applied in the depth pass for all types of projected shadows except VSM.

ShadowFadeResolution

(int32) Resolution in texel below which shadows are faded out.

ShadowFadeExponent

(float) Controls the rate at which shadows are faded out.

Texture Detail Settings

OnlyStreamInTextures

(bool) If enabled, texture will only be streamed in, not out.

MaxAnisotropy

(int32) Maximum level of anisotropy used.

FoliageDrawRadiusMultiplier

(float) Foliage draw distance scalar.

VSync Settings

UseVSync

(bool) Whether to use VSync or not.

Screen Percentage Settings

ScreenPercentage

(float) Percentage of screen main view should take up.

UpscaleScreenPercentage

(bool) Whether to upscale the screen to take up the full front buffer.

Resolution Settings

ResX

(int32) Screen X resolution.

ResY

(int32) Screen Y resolution.

Fullscreen

(bool) Fullscreen.

Mesh Settings

bForceCPUAccessToGPUSkinVerts

(bool) Whether to force CPU access to GPU skinned vertex data.