design's wheel size is too big for effectively traversing large obstacles, citing research done by Caltech and NASA on the issue. He also criticized the negative camber of the wheels for having no discernable purpose. Homing spider droid The OG-9 homing spider droid appears in Attack of the Clones during the Battle of Geonosis and features in other Star Wars media, including as a playable vehicle in Battlefront II. During post-production, the droid was referred to as "Commerce Guild droid B." Referred to in source material as the OG-9 homing spider droid, these droid walking tanks were manufactured by Baktoid Armor Workshop for the Commerce Guild to enforce their contracts. It consists of an armored reactor core body attached to four armored legs, giving it a height of . While the legs are thin they are tougher than they look, allowing the droid to traverse nearly any terrain and achieve a top speed of . Its primary weapons are two dish-shaped laser cannons mounted on the top and bottom of the reactor core: the top-mounted cannon primarily releases sustains bursts to wear down deflector shields, while the bottom cannon suppresses enemy infantry. Joe Pappalardo of Popular Mechanics praised the design of the Homing spider droid for mirroring the design of a real-world robot, RoboSimian, designed by JPL for traversing rough terrain. However he criticized it's apparent slow speed during the final battle in Attack of the Clones and argues that destroying one of its legs would quickly knock the robot out of a fight. Multi-troop transport (MTT) The Multi-Troop Transports or MTTs made their first appearance in The Phantom Menace, carrying and deploying Trade Federation battle droids during the invasion of Naboo. As with the AAT, parts of the MTT are intended to suggest animalistic traits. Lucas requested the MTT have locomotive-type qualities and be capable of knocking down everything in its path; consequently, the MTT has battering rams and locomotive components. Although the MTT was primarily created using computer-generated imagery (CGI), a scale model was also built to film certain scenes of The Phantom Menace, combining elements of practical and digital special effects. Fictional background for the MTT explains it was originally produced by Baktoid Armor Workshop, the same manufacturer of the Trade Federation's AAT. Measuring long and tall, the MTT is designed to deploy in traditional battle lines, hence its strong frontal armor. Although floating above the ground