From: Eduardo Estevez (
Date: Sat Oct 01 2022 - 06:52:56 CDT

Dear VMD users

I am trying to calculate the number of water molecules that are 3 Å from a
nanoparticle (metal oxide), however I get an error *( atomselect: cannot
parse selection text: within 3 of atomselect0*) , I have the following Tk

*set outfile [open output.txt w]set nf [molinfo top get numframes]set tube
[atomselect top "type 3 4"]set water [atomselect top "type 1 2"]for {set
i 0} {$i<$nf} {incr i} { $tube frame $i $water frame $i $tube
update $water update set a [atomselect top "within 3 of $tube"
frame $i] puts $outfile "$i $water" }close $outfile *