Unreal Engine Drives Digital Puppeteering System for The Mill and Monster.com | Unreal Engine – To produce several animations of Monster.com’s signature purple monster in record time, The Mill devised a real-time finger-driven system using Unreal Engine and a Leap Motion rig. A digital puppeteering and recording session brought the purple monster to life in real time, generating hours of finished animation in a fraction of the time of a traditional pipeline.