I've written a small (in fact very small) C++ library for using vtk and gtkmm [http://www.gtkmm.org/] together using gtkglext [http://gtkglext.sourceforge.net/]. If you are interested feel free to obtain it from http://sourceforge.net/projects/vtkmm and dont't hesitate to commend, criticize or flame it. Have fun, Matthias Langer