/ue-materials-rendering

Post-Process Settings Reference

FPostProcessSettings fields as declared in Engine/Source/Runtime/Engine/Classes/Engine/Scene.h. Every value field has a paired bOverride_<Field> bit; the value is ignored unless that bit is true.

Carriers of the struct: APostProcessVolume::Settings, UPostProcessComponent::Settings, UCameraComponent::PostProcessSettings, USceneCaptureComponent2D::PostProcessSettings.

Usage Pattern

FPostProcessSettings& S = Volume->Settings;

S.bOverride_BloomIntensity = true;
S.BloomIntensity = 1.5f;

// Without the override bit this assignment does nothing:
S.BloomIntensity = 1.5f;

Bloom

Raising BloomThreshold toward 1.0 keeps bloom on genuinely bright pixels and is closer to physical behaviour than the default catch-all.

Exposure (Eye Adaptation)

Locking exposure:

S.bOverride_AutoExposureMethod = true;
S.AutoExposureMethod = AEM_Manual;
S.bOverride_AutoExposureBias = true;
S.AutoExposureBias = 0.0f;

Setting AutoExposureMinBrightness equal to AutoExposureMaxBrightness also pins adaptation while keeping the histogram path.

Depth of Field

DepthOfFieldFstop = 1.4 with DepthOfFieldFocalDistance = 200 gives a portrait-style shallow focus; Fstop = 22 is near-infinite focus.

Color Grading

All grading fields are FVector4 — RGB plus a master component in W.

// Desaturated shadows, warm highlights
S.bOverride_ColorSaturationShadows = true;
S.ColorSaturationShadows = FVector4(0.5f, 0.5f, 0.5f, 1.0f);
S.bOverride_ColorGainHighlights = true;
S.ColorGainHighlights = FVector4(1.05f, 0.98f, 0.9f, 1.0f);

ColorSaturation = FVector4(0, 0, 0, 1) is full greyscale.

Filmic tonemapper controls live alongside them: FilmSlope, FilmToe, FilmShoulder, FilmBlackClip, FilmWhiteClip.

Vignette and Film Grain

Ambient Occlusion

Global Illumination and Reflections

EDynamicGlobalIlluminationMethod::Type and EReflectionMethod::Type are declared in Engine/EngineTypes.h; ELumenRayLightingModeOverride in Engine/Scene.h.

Raising LumenSceneDetail helps interiors where surface-cache misses produce splotchy GI. HitLightingForReflections trades GPU time for accurate mirror-like reflections. Reducing LumenMaxTraceDistance is a cheap win in enclosed levels.

MegaLights

S.bOverride_bMegaLights = true;
S.bMegaLights = true;

The project default is URendererSettings::bEnableMegaLights (r.MegaLights.EnableForProject). MegaLights needs hardware ray tracing or, as fallback, software (Lumen) tracing data (MegaLights::HasRequiredTracingData, Renderer/Private/MegaLights/MegaLights.cpp:541), replaces the other direct-lighting and shadowing paths for the lights it handles, and skips directional lights unless r.MegaLights.DirectionalLights=1 (default 0, MegaLights.cpp:239). Runtime CVars include r.MegaLights.Allowed, r.MegaLights.HardwareRayTracing and r.MegaLights.Denoiser.

Screen Space Reflections

Used when ReflectionMethod is ScreenSpace.

Motion Blur

Lens Artefacts

Blendables (Post-Process Materials)

FPostProcessSettings holds a FWeightedBlendables WeightedBlendables array. Do not edit it directly; use:

void AddBlendable(TScriptInterface<IBlendableInterface> InBlendableObject, float InWeight);
void RemoveBlendable(TScriptInterface<IBlendableInterface> InBlendableObject);

APostProcessVolume, UPostProcessComponent and UCameraComponent each forward to AddBlendable through AddOrUpdateBlendable(TScriptInterface<IBlendableInterface> InBlendableObject, float InWeight = 1.0f).

// A material or a MID both satisfy IBlendableInterface.
Volume->AddOrUpdateBlendable(OutlineMaterial, 1.0f);

UMaterialInstanceDynamic* OutlineMID = UMaterialInstanceDynamic::Create(OutlineMaterial, this);
OutlineMID->SetScalarParameterValue(TEXT("Thickness"), 2.f);
Volume->AddOrUpdateBlendable(OutlineMID, 1.0f);

The material's MaterialDomain must be MD_PostProcess (MaterialDomain.h). Its BlendableLocation field selects where the pass runs; EBlendableLocation (Engine/BlendableInterface.h):

Ordering within one location is UMaterial::BlendablePriority. UMaterial::bIsBlendable controls whether several weighted instances of the material at one location are merged into one pass with interpolated parameters (false gives each its own pass; a material with a UserSceneTexture output is never merged, Material.cpp:2097), and UMaterial::UserSceneTexture names a user scene texture the pass writes.

Volume Priority and Blending

BackgroundVolume->Priority = 1.f;
DangerVolume->Priority = 10.f;   // wins wherever both apply

Only properties whose bOverride_* bit is set participate; everything else falls through to the next volume down.

Presets

Dark and oppressive

FPostProcessSettings& S = Volume->Settings;

S.bOverride_BloomIntensity = true;            S.BloomIntensity = 0.2f;
S.bOverride_VignetteIntensity = true;         S.VignetteIntensity = 1.0f;
S.bOverride_ColorSaturation = true;           S.ColorSaturation = FVector4(0.6f, 0.6f, 0.6f, 1.0f);
S.bOverride_AutoExposureMinBrightness = true; S.AutoExposureMinBrightness = 0.01f;
S.bOverride_AutoExposureMaxBrightness = true; S.AutoExposureMaxBrightness = 1.0f;
S.bOverride_FilmGrainIntensity = true;        S.FilmGrainIntensity = 0.8f;

High-contrast cinematic

FPostProcessSettings& S = Volume->Settings;

S.bOverride_BloomIntensity = true;            S.BloomIntensity = 0.5f;
S.bOverride_ColorContrast = true;             S.ColorContrast = FVector4(1.3f, 1.3f, 1.3f, 1.0f);
S.bOverride_ColorSaturation = true;           S.ColorSaturation = FVector4(1.2f, 1.2f, 1.2f, 1.0f);
S.bOverride_DepthOfFieldFstop = true;         S.DepthOfFieldFstop = 2.0f;
S.bOverride_DepthOfFieldFocalDistance = true; S.DepthOfFieldFocalDistance = 500.0f;
S.bOverride_MotionBlurAmount = true;          S.MotionBlurAmount = 0.4f;

Tech overlay

FPostProcessSettings& S = Volume->Settings;

S.bOverride_BloomIntensity = true;             S.BloomIntensity = 2.0f;
S.bOverride_SceneFringeIntensity = true;       S.SceneFringeIntensity = 2.0f;
S.bOverride_ColorSaturationHighlights = true;  S.ColorSaturationHighlights = FVector4(0.7f, 1.2f, 1.4f, 1.0f);
S.bOverride_VignetteIntensity = true;          S.VignetteIntensity = 0.6f;

Suppress a volume

Volume->BlendWeight = 0.0f;   // keeps the settings, contributes nothing
Volume->bEnabled = false;     // removes it from the blend entirely