Some people said Isabel Wilkerson’s book “Caste” was unadaptable. The subject matter was too heavy and too academic. But Ava DuVernay had a vision – and she pursued an unusual funding model to get her new film “Origin” made. Read more:When filmmaker Ava DuVernay couldn’t get traditional financing to film “Origin,” the Ford Foundation, Melinda Gates and other philanthropists stepped in. National arts reporter Geoff Edgers says it might be cinema’s new business model.Today’s show was produced by Peter Bresnan. It was mixed by Rennie Svirnovskiy. It was edited by Maggie Penman. Subscribe to The Washington Post here.