Hi Tiglath, There is no option to randomly delete. You need to specify residue numbers or names, or use selection, e.g. delete :246,300-312,43 delete #0:212.A delete sel ... where "sel" in the latter means the current selection. There are many more examples of command-line atom specification in this page: <https://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/frameatom_spec.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On Jan 4, 2021, at 9:47 AM, Moradkhan, Tiglath A <tmoradkhan@csus.edu> wrote:

Hi I've built a lipid particle containing 252 molecules and I'm trying to randomly delete 20 lipid molecules. Does the delete command allow this? I've tried using it but it doesn't seem to work for this case. Thanks Tiglath