Son of a camera engineer, Allder worked as an assistant cameraman on commercials for 8 years before moving to effects in films. Special effects supervisor who entered film in 1968 as a technician on A TWIST OF SAND. Other notable credits include mechanical effects supervisor on STAR WARS: EPISODE V - THE EMPIRE STRIKES BACK (1980), CONAN THE BARBARIAN (1982, special effects) and special effects supervisor for THE KEEP (1983), TOP SECRET! (1984), LEGEND and THE JEWEL OF THE NILE (both 1985), SOLARBABIES (1986), THE PRINCESS BRIDE (1987), THE RESCUE (1988), BRAVEHEART (1995), MUPPET TREASURE ISLAND (1996), THE FIFTH ELEMENT (1997), LOST IN SPACE (1998), THE CRIMINAL (2000), BEHIND ENEMY LINES (2001), BLADE II (2002), UNDERWORLD (2003), HELLBOY (2004), THE CAVE and AN AMERICAN HAUNTING (both 2005), and BLOOD AND CHOCOLATE and THE SEEKER: THE DARK IS RISING (both 2007).  Visual Effects 1979: ALIEN (w. Carlo Rambaldi, H. R. Giger, Brian Johnson & Denys Ayling) 1 nomination, 1 Award