Hi John, There are several ways to select atoms, but I guess you mean "picking" them from the screen. By default, picking two atoms would be done with Ctrl-click on the first atom, then Shift-Ctrl-click on the second. The shift is needed to add to the selection instead of replacing it. How to select is described here: <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/selection.html> and in the getting started tutorial <http://www.cgl.ucsf.edu/Outreach/Tutorials/GettingStarted.html#MenuMouse
Or, if you are looking at the Distances tool, you could press its Help button to see its man page, which lists the ways to add the measurement and includes links to the selection page. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco On Jan 19, 2010, at 5:02 AM, Beale, John wrote:
Hello, I am trying to measure distances between atoms using the Tools -> Structure Analysis -> Distances routine. Chimera is requesting that two atoms must be selected in the main graphics window for this to work. I can’t figure out how to select the atoms. Can someone help me? John