Hi, The centroid feature is great, but I would like to select two centroids of a centroid and an atom and then measure the distance between them. When I try this I get the Error Message: "Exactly two atoms must be selected in the graphics window". Is there anyway to add the ability to make these measurements. Thanks, Dave -------------------------------------------------------- David Chenoweth NIH Postdoctoral Fellow Swager Research Group Massachusetts Institute of Technology Chemistry Department, 18-053 77 Massachusetts Avenue Cambridge, MA 02139 Email: dcheno@mit.edu Lab Phone: 617-258-6537 --------------------------------------------------------