Another difference is that machinima is created in real time, but other animation is pre-rendered. Real-time engines need to trade quality for speed and use simpler algorithms and models. In the 2001 animated film "", every strand of hair on a character's head was independent; real-time needs would likely force them to be treated as a single unit. Kelland, Morris, and Lloyd argue that improvement in consumer-grade graphics technology will allow more realism; For cut scenes in video games, issues other than visual fidelity arise. Pre-rendered scenes can require more digital storage space, weaken suspension of disbelief through contrast with real-time animation of normal gameplay, and limit interaction.