OpenToonz is a full production-grade 2D animation suite originally built as Toonz in Italy and later customized extensively inside Studio Ghibli for films including Princess Mononoke and The Secret World of Arrietty. Dwango released the codebase as free, open-source software so independent animators, students, and studios worldwide can access the same rigging, scanning, coloring, and compositing tools once reserved for major animation houses.