The programs VMD and NAMD has a program called psfgen. Check out the website <a href="http://www.ks.uiuc.edu/Research/vmd/plugins/psfgen/">http://www.ks.uiuc.edu/Research/vmd/plugins/psfgen/</a> for info. Cheers, Shawn <div class="gmail_quote">On Jan 20, 2008 5:11 PM, Jack Shultz <<a href="mailto:jackyg...@gmail.com">jackyg...@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Is there any GPL software for generating PSF ? </blockquote></div>