OpenToonz is the same software used to make films like Spirited Away, and TV shows like Steven Universe and Futurama now available to everyone as Open Source.
Since the software "Toonz," which is the original version of OpenToonz, was first used for some Princess Mononoke cuts, it has been utilized in the ink and paint, color design, and digital composition process(*) of almost all of works of Studio Ghibli. After "Arrietty/The Secret World of Arrietty," it was customized inside the company and evolved to become more usable according to its production style.
OpenToonz is equipped with unique functions that have repeatedly been improved based on production staff's opinions, including the scanning tool "GTS" specializing in animation, which was developed in Studio Ghibli. For details, see "Introduction to the functions unique to OpenToonz" written below.