These ebuilds come from http://gentoo.zugaina.org/.
If you have some problems, go to the official site first.
octave : GNU Octave is a high-level language (MatLab compatible) intended for numerical computations ( http://www.octave.org/ )
opencascadelib : Ebuild for opencascadelib-5.2 ( http://www.opencascade.org/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a zugaina
For Paludis use this rsync : rsync://gentoo.zugaina.org/zugaina-portage
If you have a problem : ycarus(-at-)zugaina.org