o understand Ncam's origins, we need to rewind back to 1999 and production of the first film, when Nic Hatch was working at Mill Film as previs supervisor under Rob Legato. An acclaimed VFX supervisor that had, Legato was keen to visualise some of the film's more magical shots through the camera lens. The shot in question saw boats gliding towards Hogwarts as the camera tilts to reveal the enchanting castle for the first time. It was based on a system called Free-d, developed by the BBC and MPC, whereby a witness camera on the main cine camera looked up at unique circular markers (fiducials) mounted in the ceiling trusses and worked out the position and orientation. The Hogwarts previs model was mixed and overlaid with the live action of the boats.
