Home page is at http://www.tls.cena.fr/~mertz/index_e.html
I rather use perl than tcl.
However in my team, we developed TkZinc a tcl widget also known as Zinc, a Canvas supporting openGL and many new interesting functions which should be worth for the tcl community.
It is available at http://www.openatc.org/zinc . EF Site has moved to new owner