A third unit, headed by Derek Meddings and his assistant Mike Trim, handled special effects and miniatures and was tasked with creating all the permanent sets and models to be used from the pilot episode, such as the Cloudbase interiors and scaled-down Spectrum Pursuit Vehicles. A design innovation for this series meant that the noses of the miniature vehicles would "dip" when stopped, to imitate the sudden application of brakes and deceleration on a real-life vehicle.[8] The miniature of the Cloudbase exterior, which ran to six feet (1.8 m) in length, proved to be too heavy to be held up with strings and was instead supported by a metal pole.[46][47] To transfer the Mysteron rings from script to screen, the production team acted on the advice of producer Reg Hill, who suggested that a transparency be made that could be panned across the puppet sets using a slide projector.[32]