I would like to delete all water residues that are in steric clash with lipid residues. What I have is a single pdb file that includes both types of residues. Can't have the two as different models. Therefore I can't apply the zone tool that I know how to manage for two different models. The only alternative I can figure out is through the "Find Clashes,Contacts", writing a file for all WAT at a specified distance from the lipid residues and then manually deleting, or inventing a script for that (at <=0.6A there are 386 clashes). Hope to have missed an automatic tool from Chimera. If not, I suggest that as a most useful additional tool for cleaning systems. I dropped into the problem when at the first minimization, in view of MD, the system met segmentation fault after a few steps, with gradient decreasing by eight orders of magnitude along those few steps. Then I recognized not to have been careful enough before making the coordinate files for the MD suite. I should have not relied too much in the membrane builder and I had better spent time in checking for steric clashes. Thanks francesco pietra ____________________________________________________________________________________ Get easy, one-click access to your favorites. Make Yahoo! your homepage. http://www.yahoo.com/r/hs