Hello Ran, In your screenshot, the @ symbol is missing in the commands. The atom specification #1:1-2 in the screenshot means "model 1, residues 1-2", but this molecule has no residues because it is not a polymer. This is why the resulting selection is empty. I suspect the command you mention in your email wouldn’t work either, because it has both : and @ (or maybe the : selector would just be ignored since you provide no residue name or number, and since doing so results in an empty selection but no error based on your screenshot). Try this instead: sel #1@1-2 (you might have to adjust the atom numbers to select the ones you want). I hope this helps, Guillaume On 2 Apr 2024, at 16:46, 洪冉 via ChimeraX-users <chimerax-users@cgl.ucsf.edu<mailto:chimerax-users@cgl.ucsf.edu>> wrote: Dear Users and Developers of ChimeraX, I am attempting to make a selection of a range of atoms by their numbers in ChimeraX. However, the command I have used does not seem to work in my case. The command in question is sel #1:@1-3. Could anyone assist me with this issue? For screenshots, please see below. Many thanks in advance! Ran <Snipaste_2024-04-02_22-39-03.jpg> VARNING: Klicka inte på länkar och öppna inte bilagor om du inte känner igen avsändaren och vet att innehållet är säkert. CAUTION: Do not click on links or open attachments unless you recognise the sender and know the content is safe. <Snipaste_2024-04-02_22-39-03.jpg>_______________________________________________ ChimeraX-users mailing list -- chimerax-users@cgl.ucsf.edu<mailto:chimerax-users@cgl.ucsf.edu> To unsubscribe send an email to chimerax-users-leave@cgl.ucsf.edu<mailto:chimerax-users-leave@cgl.ucsf.edu> Archives: https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/ När du har kontakt med oss på Uppsala universitet med e-post så innebär det att vi behandlar dina personuppgifter. För att läsa mer om hur vi gör det kan du läsa här: http://www.uu.se/om-uu/dataskydd-personuppgifter/ E-mailing Uppsala University means that we will process your personal data. For more information on how this is performed, please read here: http://www.uu.se/en/about-uu/data-protection-policy