These ebuilds come from http://s3d.berlios.de/.
If you have some problems, go to the official site first.
libg3d : library for loading 3D models of many file types ( https://gna.org/projects/libg3d/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a s3d
For Paludis use this rsync : rsync://gentoo.zugaina.org/s3d-portage
If you have a problem : ycarus(-at-)zugaina.org