Hi Fred, It may be because your selection name starts with a number. The select command may be more finicky than others because it is overloaded with two different functions, activation of models for motion (indicated by model number without #) and selection of atoms (indicated by model number with # or other specification symbol such as : for residues or @ for atoms). Parsing the select command to try to identify the former case may interfere with recognizing your selection names. I tried making overlapping named selections: sel1a, sel1b and in that case you could accomplish your example with sel sel1a & sel1b & without CA/C1' (the last part means side chain atoms not including the CA/C1', could also use "with CA/C1' "; these are terminal entries under the Select... Structure menu, which can be used as command-line specifiers) I personally prefer to skip selections altogether and instead use the "alias" command in a similar manner. People may gravitate to using named selections because of Pymol terminology. If I understand correctly, Pymol named selections are more like Chimera aliases. For example: alias set1 :10-20.a alias set2 :15-35 sel set1 & set2 & ~ element.H ... see Built-In Classifications and Combinations ... <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/frameatom_spec.html> alias command: <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/alias.html> The aliases wouldn't appear in the menu, however, except for "function" aliases as described in the documentation above. 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 31, 2012, at 12:27 PM, frederick lee wrote:
dear chimera users, i can defined named selections and they work under the select menu.
however, i canNOT use the command line to select them; e.g., i have 4 named selections 0a,0b,1a,1b
dis 0a | 1a works sel 1a NOT working sel :1a NOT working (said selection cleared)
i like to be able to select multiple named selections and further apply filters on them; e.g.,
"select 1a and 1b and atoms=side chain atoms"
how do i accomplish this? as always thank you very much. fred