Leslie Iwerks, granddaughter of Mickey Mouse co-creator Ub Iwerks, has started work on a Disney-commissioned documentary about its Imagineering division.Iwerks revealed the project Friday at Hearst Castle at the West Coast premiere of her documentary “Citizen Hearst.” She said she’s been working on the Imagineering project since last year and plans to finish in time for a 2016 release that will coincide with the opening of Disney’s Shanghai theme park in China. Imagineering was created in 1952 by Walt Disney to oversee the design and production of Disneyland, which opened three years later. Disney adopted the term to characterize the mix of imagination and engineering by the divisions employees, dubbed Imagineers. The Glendale-based division of Walt Disney Co. has been granted more than 100 patents and designed 11 Disney theme parks, resorts, cruise ships and other entertainment venues. Iwerks said she’s been pleased at the level of access, noting, “They gave me the keys to the kingdom.” Her first documentary, 1999′s “The Hand Behind the Mouse: The Ub Iwerks Story,” was also commissioned by and released by Disney. Her grandfather received two Oscars for his technical achievements.