How Aardman faked a marching robot army for Wallace & Gromit: Vengeance Most Fowl without building dozens of puppets

For a scene needing a marching crowd of small robot henchmen ("Norbots") in Wallace & Gromit: Vengeance Most Fowl, Aardman avoided building dozens of individual puppets. Co-director Merlin Crossingham described animating a single row of five puppets against blue screen, then moving the whole row backward on a motion-control track between exposures and repeating the cycle across twelve rows of depth, before compositing layered the passes into one crowd. The repositioning had to happen for real on the rig rather than by duplicating one photographed row digitally, because each row sat in a different position relative to the set's practical lighting -- "they were going through light, we couldn't just do one and repeat it," in Crossingham's words. Folded into the Wiki's page on motion control in stop motion as a worked example of the rig repositioning the subject rather than the camera.