http://www.dawnarc.com/2016/10/ue4%E5%A6%82%E4%BD%95%E6%9B%BF%E6%8D%A2%E8%A7%92%E8%89%B2mesh%E4%B8%8A%E7%9A%84material%E6%9D%90%E8%B4%A8/

.h (located in pawn header file and assigned in Blueprint editor)

UPROPERTY(EditAnywhere)TArray<UMaterialInterface*> Materials;TSubclassOf<class AMyPawn> PawnClass;FVector spawnLocation = FVector(0.0f, 0.0f, 0.0f);FRotator spawnRotation = FRotator::ZeroRotator;AMyPawn* pawn = GetWorld()->SpawnActor<AMyPawn>(PawnClass, spawnLocation, spawnRotation);if (pawn != nullptr){    AMyPawn* defaultPawn = PawnClass.GetDefaultObject();    int32 materialCount = defaultPawn->Materials.Num();    int m = FMath::RandRange(0, materialCount - 1);    const TArray<UActorComponent*>& theComponents = pawn->GetComponents();    int32 componentCount = theComponents.Num();    for (int32 x = 0; x < componentCount; x++)    {        USkeletalMeshComponent* mesh = Cast<USkeletalMeshComponent>(theComponents[x]);        if (mesh != nullptr)        {            mesh->SetMaterial(0, defaultPawn->Materials[m]);        }    }TAGGED IN

.h (located in pawn manager responsible for spawning them)

.cpp