MyPawn.cpp

  static ConstructorHelpers::FObjectFinder<UMaterial> MaterialFinder(*SelectionMaterialPath);
  if (MaterialFinder.Succeeded()) {
    SelectionDecalMaterial = MaterialFinder.Object;
    SelectionDecalMaterialInstance = UMaterialInstanceDynamic::Create(SelectionDecalMaterial, this);
    SelectionDecal = CreateDefaultSubobject<UDecalComponent>(TEXT("SelectionDecal"));
    SelectionDecal->AttachTo(RootComponent);
    SelectionDecal->SetDecalMaterial(SelectionDecalMaterialInstance);
  }