diff --git a/Source/glTFRuntime/Private/glTFRuntimeParserMaterials.cpp b/Source/glTFRuntime/Private/glTFRuntimeParserMaterials.cpp
index e255ff1..965b7cb 100644
--- a/Source/glTFRuntime/Private/glTFRuntimeParserMaterials.cpp
+++ b/Source/glTFRuntime/Private/glTFRuntimeParserMaterials.cpp
@@ -329,6 +329,37 @@ UMaterialInterface* FglTFRuntimeParser::LoadMaterial_Internal(const int32 Index,
 			GetMaterialTexture(JsonMaterialSheen->ToSharedRef(), "sheenRoughnessTexture", false, RuntimeMaterial.SheenRoughnessTextureCache, RuntimeMaterial.SheenRoughnessTextureMips, RuntimeMaterial.SheenRoughnessTextureTransform, RuntimeMaterial.SheenRoughnessTextureSampler, false);
 			RuntimeMaterial.bKHR_materials_sheen = true;
 		}
+
+		// KHR_materials_iridescence
+		const TSharedPtr<FJsonObject>* JsonMaterialIridescence;
+		if ((*JsonExtensions)->TryGetObjectField(TEXT("KHR_materials_iridescence"), JsonMaterialIridescence))
+		{
+			if (!(*JsonMaterialIridescence)->TryGetNumberField(TEXT("iridescenceFactor"), RuntimeMaterial.IridescenceFactor))
+			{
+				RuntimeMaterial.IridescenceFactor = 0;
+			}
+
+			if (!(*JsonMaterialIridescence)->TryGetNumberField(TEXT("iridescenceIor"), RuntimeMaterial.IridescenceIor))
+			{
+				RuntimeMaterial.IridescenceIor = 1.3;
+			}
+
+			if (!(*JsonMaterialIridescence)->TryGetNumberField(TEXT("iridescenceThicknessMinimum"), RuntimeMaterial.IridescenceThicknessMinimum))
+			{
+				RuntimeMaterial.IridescenceThicknessMinimum = 100;
+			}
+
+			if (!(*JsonMaterialIridescence)->TryGetNumberField(TEXT("iridescenceThicknessMaximum"), RuntimeMaterial.IridescenceThicknessMaximum))
+			{
+				RuntimeMaterial.IridescenceThicknessMaximum = 400;
+			}
+
+			GetMaterialTexture(JsonMaterialIridescence->ToSharedRef(), "iridescenceTexture", false, RuntimeMaterial.IridescenceTextureCache, RuntimeMaterial.IridescenceTextureMips, RuntimeMaterial.IridescenceTextureTransform, RuntimeMaterial.IridescenceTextureSampler, false);
+			GetMaterialTexture(JsonMaterialIridescence->ToSharedRef(), "iridescenceThicknessTexture", false, RuntimeMaterial.IridescenceThicknessTextureCache, RuntimeMaterial.IridescenceThicknessTextureMips, RuntimeMaterial.IridescenceThicknessTextureTransform, RuntimeMaterial.IridescenceThicknessTextureSampler, false);
+
+			RuntimeMaterial.bKHR_materials_iridescence = true;
+		}
+
 	}
 
 	if (IsInGameThread())
@@ -649,18 +680,33 @@ UMaterialInterface* FglTFRuntimeParser::BuildMaterial(const int32 Index, const F
 	{
 		if (MaterialsConfig.bUseSubstrateMaterials && !RuntimeMaterial.bKHR_materials_unlit && !RuntimeMaterial.bKHR_materials_pbrSpecularGlossiness)
 		{
-			EglTFRuntimeSubstrateMaterialType SubstrateMaterialType = RuntimeMaterial.bTwoSided ? EglTFRuntimeSubstrateMaterialType::OpaqueTwoSided : EglTFRuntimeSubstrateMaterialType::Opaque;
+			bool bIsSimpleSlab = true;
+			if (RuntimeMaterial.bKHR_materials_clearcoat ||	RuntimeMaterial.bKHR_materials_iridescence || RuntimeMaterial.bKHR_materials_sheen || RuntimeMaterial.bKHR_materials_volume)
+			{
+				bIsSimpleSlab = false;
+			}
+
+			EglTFRuntimeSubstrateMaterialType SubstrateMaterialType = RuntimeMaterial.bTwoSided ?
+				(bIsSimpleSlab ? EglTFRuntimeSubstrateMaterialType::SimpleOpaqueTwoSided : EglTFRuntimeSubstrateMaterialType::OpaqueTwoSided) :
+				(bIsSimpleSlab ? EglTFRuntimeSubstrateMaterialType::SimpleOpaque : EglTFRuntimeSubstrateMaterialType::Opaque);
+
 			if (RuntimeMaterial.bKHR_materials_transmission)
 			{
-				SubstrateMaterialType = RuntimeMaterial.bTwoSided ? EglTFRuntimeSubstrateMaterialType::TransmittanceTwoSided : EglTFRuntimeSubstrateMaterialType::Transmittance;
+				SubstrateMaterialType = RuntimeMaterial.bTwoSided ?
+					(bIsSimpleSlab ? EglTFRuntimeSubstrateMaterialType::SimpleTransmittanceTwoSided : EglTFRuntimeSubstrateMaterialType::TransmittanceTwoSided) :
+					(bIsSimpleSlab ? EglTFRuntimeSubstrateMaterialType::SimpleTransmittance : EglTFRuntimeSubstrateMaterialType::Transmittance);
 			}
 			else if (RuntimeMaterial.bTranslucent)
 			{
-				SubstrateMaterialType = RuntimeMaterial.bTwoSided ? EglTFRuntimeSubstrateMaterialType::AlphaCompositeTwoSided : EglTFRuntimeSubstrateMaterialType::AlphaComposite;
+				SubstrateMaterialType = RuntimeMaterial.bTwoSided ?
+					(bIsSimpleSlab ? EglTFRuntimeSubstrateMaterialType::SimpleAlphaCompositeTwoSided : EglTFRuntimeSubstrateMaterialType::AlphaCompositeTwoSided) :
+					(bIsSimpleSlab ? EglTFRuntimeSubstrateMaterialType::SimpleAlphaComposite : EglTFRuntimeSubstrateMaterialType::AlphaComposite);
 			}
 			else if (RuntimeMaterial.bMasked)
 			{
-				SubstrateMaterialType = RuntimeMaterial.bTwoSided ? EglTFRuntimeSubstrateMaterialType::MaskedTwoSided : EglTFRuntimeSubstrateMaterialType::Masked;
+				SubstrateMaterialType = RuntimeMaterial.bTwoSided ?
+					(bIsSimpleSlab ? EglTFRuntimeSubstrateMaterialType::SimpleMaskedTwoSided : EglTFRuntimeSubstrateMaterialType::MaskedTwoSided) :
+					(bIsSimpleSlab ? EglTFRuntimeSubstrateMaterialType::SimpleMasked : EglTFRuntimeSubstrateMaterialType::Masked);
 			}
 
 			if (MaterialsConfig.SubstrateMaterials.Contains(SubstrateMaterialType))
@@ -956,6 +1002,23 @@ UMaterialInterface* FglTFRuntimeParser::BuildMaterial(const int32 Index, const F
 			TextureCompressionSettings::TC_Default, false);
 	}
 
+	ApplyMaterialFloatFactor(RuntimeMaterial.bKHR_materials_iridescence, "iridescenceFactor", RuntimeMaterial.IridescenceFactor);
+	ApplyMaterialFloatFactor(RuntimeMaterial.bKHR_materials_iridescence, "iridescenceIor", RuntimeMaterial.IridescenceIor);
+	ApplyMaterialFloatFactor(RuntimeMaterial.bKHR_materials_iridescence, "iridescenceThicknessMaximum", RuntimeMaterial.IridescenceThicknessMaximum);
+	ApplyMaterialFloatFactor(RuntimeMaterial.bKHR_materials_iridescence, "iridescenceThicknessMinimum", RuntimeMaterial.IridescenceThicknessMinimum);
+	if (RuntimeMaterial.bKHR_materials_iridescence)
+	{
+		ApplyMaterialTexture("iridescenceTexture", RuntimeMaterial.IridescenceTextureCache, RuntimeMaterial.IridescenceTextureMips,
+			RuntimeMaterial.IridescenceTextureSampler,
+			"iridescence", RuntimeMaterial.IridescenceTextureTransform,
+			TextureCompressionSettings::TC_Default, true);
+
+		ApplyMaterialTexture("iridescenceThicknessTexture", RuntimeMaterial.IridescenceThicknessTextureCache, RuntimeMaterial.IridescenceThicknessTextureMips,
+			RuntimeMaterial.IridescenceThicknessTextureSampler,
+			"iridescenceThickness", RuntimeMaterial.IridescenceThicknessTextureTransform,
+			TextureCompressionSettings::TC_Default, true);
+	}
+
 	ApplyMaterialFloatFactor(RuntimeMaterial.bKHR_materials_emissive_strength, "emissiveStrength", RuntimeMaterial.EmissiveStrength);
 
 	for (const TPair<FString, float>& Pair : MaterialsConfig.ScalarParamsOverrides)
diff --git a/Source/glTFRuntime/Public/glTFRuntimeParser.h b/Source/glTFRuntime/Public/glTFRuntimeParser.h
index 63aa891..dcb8f1c 100644
--- a/Source/glTFRuntime/Public/glTFRuntimeParser.h
+++ b/Source/glTFRuntime/Public/glTFRuntimeParser.h
@@ -437,6 +437,14 @@ enum class EglTFRuntimeMaterialType : uint8
 UENUM()
 enum class EglTFRuntimeSubstrateMaterialType : uint8
 {
+	SimpleOpaque,
+	SimpleOpaqueTwoSided,
+	SimpleTransmittance,
+	SimpleTransmittanceTwoSided,
+	SimpleAlphaComposite,
+	SimpleAlphaCompositeTwoSided,
+	SimpleMasked,
+	SimpleMaskedTwoSided,
 	Opaque,
 	OpaqueTwoSided,
 	Transmittance,
@@ -2202,6 +2210,19 @@ struct FglTFRuntimeMaterial
 	FglTFRuntimeTextureTransform SheenRoughnessTextureTransform;
 	FglTFRuntimeTextureSampler SheenRoughnessTextureSampler;
 
+	bool bKHR_materials_iridescence;
+	double IridescenceFactor;
+	double IridescenceIor;
+	double IridescenceThicknessMaximum;
+	double IridescenceThicknessMinimum;
+	UTexture2D* IridescenceTextureCache;
+	TArray<FglTFRuntimeMipMap> IridescenceTextureMips;
+	FglTFRuntimeTextureSampler IridescenceTextureSampler;
+	FglTFRuntimeTextureTransform IridescenceTextureTransform;
+	UTexture2D* IridescenceThicknessTextureCache;
+	TArray<FglTFRuntimeMipMap> IridescenceThicknessTextureMips;
+	FglTFRuntimeTextureSampler IridescenceThicknessTextureSampler;
+	FglTFRuntimeTextureTransform IridescenceThicknessTextureTransform;
 
 	FglTFRuntimeMaterial()
 	{
@@ -2253,6 +2274,13 @@ struct FglTFRuntimeMaterial
 		SheenRoughnessFactor = 0;
 		SheenColorTextureCache = nullptr;
 		SheenRoughnessTextureCache = nullptr;
+		bKHR_materials_iridescence = false;
+		IridescenceFactor = 0;
+		IridescenceIor = 1.3;
+		IridescenceThicknessMaximum = 400;
+		IridescenceThicknessMinimum = 100;
+		IridescenceTextureCache = nullptr;
+		IridescenceThicknessTextureCache = nullptr;
 	}
 };