Neill Blomkamp’s forte is pitting outsiders against mainstream society, the unrepresented against the privileged, ethics versus entrenched self-interest (in the spectacular “District 9” in 2009 and the so-so “Elysium ” in 2013). With “Chappie,” he expands on these ideas to explore the nature of what it means to be human — with mixed results. In the near future, crime in Johannesburg, South Africa, is kept at bay by an oppressive mechanized, robotic police force created by a gigantic corporation more interested in the bottom line than justice. One robot — Chappie — is given sentient consciousness by a misguided programmer (Dev Patel), who hopes to create androids that have the ability to think and feel for themselves. Unfortunately, Chappie is taken in by a trio of vicious criminals in need of a big score. Hoping to prep Chappie to help them with their heist, they turn him into a robotic thug with all the accoutrements of low-life criminality (at least the cinematic variety): heavy necklaces, street slang, macho violence, etc. Meanwhile, the robotic corporation goes after Chappie in an effort to shut him down, leading to a series of wild futuristic battles between robots and humans and robots and other robots. It’s all a bit silly — kind of “Short Circuit” on steroids — and Blomkamp’s efforts to show a soft side to the criminals becomes laughable. Patel and co-stars Hugh Jackman and Sigourney Weaver are wasted as they take a back seat to the bad guys and the special effects.Vitals: Director: Neill Blomkamp. Stars: Hugh Jackman, Dev Patel, Sigourney Weaver, Sharlto Copley (voice), Yo-Landi Visser, Ninja. 2015, CC, MPAA rating: R, 114 min., Science Fiction, Box office gross: $31.338 million, Sony. Extras: “We Are Tetravaal” featurette in which Weaver, Jackman and Patel discuss their characters and on-set experiences. Blu-ray adds alternate ending; extended scene “A Very Bad Man”; eight featurettes: “Chappie: The Streetwise Professor,” an inside look at Chappie and casting Copley to play the robot and his performance via motion capture, “Arms Race: The Weapons and Robots,” offers deeper look at the real-world firepower tech and the design of the “Scout” robots and “Moose,” “Bringing Chappie to Life: The Visual Effects,” “From Tetra Vaal to Chappie,” an in-depth exploration of the scriptwriting process, the early concept design work and other aspects of pre-production, “Keep It Gangster,” a behind-the-scenes look at the process of creating an authentic South African gangster world, “The Reality of Robotics,” “Jozi: Real City and a Sci-Fi Setting,” “Rogue Robot: Deconstructing the Stunts and Special Effects”; “The Art of Chappie” photo gallery.