The Opencascade license has been discussed on Debian mailling lists, here and here. One problem is that it’s built with Jonathan R. Shewchuk mesh (Triangle).
Opencascade need to be patched to build on Debian Sid. I wrote a post concerning this but Jason Kraftcheck made a much better work, providing patches which fix many problems.
It would be nice to have Debian package for Opencascade to easy install tools such as: