Yesterday I got lost listening celtic music on Youtube, ending up listening to many tunes and songs from Brave movie. I love that movie and especially its soundtracks. The Wikipedia entry says that
Brave … is their first film animated with a new proprietary animation system, called Presto.
Well, I’d rather say that Presto is private, unreleased, internal software, rather than proprietary software as I prefer to use the term proprietary for programs released to the public.
Of course it is non-free as opposed as free-as-in-freedom software, better named “software libre” or “software libero”. It looks to me more than a trade secret.
I can’t blame them for not releasing it. Its their choice.