The Sin Function

Result

Blueprit

item.h

private:
	float RunningTime;
	float Amplitude = 0.5f;
	float TimeConstant = 5.f;

item.cpp

void AItem::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

	RunningTime += DeltaTime;

	float DeltaZ = Amplitude * FMath::Sin(RunningTime * TimeConstant);

	AddActorWorldOffset(FVector(0.f, 0.f, DeltaZ));

	DRAW_SPHERE_SingleFrame(GetActorLocation());
	DRAW_VECTOR_SingleFrame(GetActorLocation(), GetActorLocation() + GetActorForwardVector() * 100);
}