Hi Phenix users, since I had to answer this very same question off-list three times in past 48 hours, I thought I post this for future reference... Yes, thanks *Billy* there is a GUI for phenix.real_space_refine (tool to refine atomic models against maps, such as cryo-EM maps)! To give it a try, you need: 1) Get the latest nightly build, dev-2427 for instance: http://phenix-online.org/download/nightly_builds.cgi 2) Enable alpha-test programs in Phenix GUI. To do this: -- start Phenix GUI; -- go to Preferences and tick "Enable alpha-test programs and features" box; -- restart the GUI (close down, then start again); -- phenix.real_space_refine will be available in Refinement section on the right (Real-space refinement [alpha]). Note, it has a very handy feature to see/explore/edit secondary-structure restraints graphically. Also note that *this is alpha-test version meaning that glitches are not unexpected*! However your feedback will help to improve it, so please let us know should you encounter problems, have suggestions or found bug(s)! All the best, Pavel