From: Maxim Belkin (mbelkin_at_ks.uiuc.edu)
Date: Fri Sep 26 2014 - 11:30:58 CDT

Sure:

set sel1 [atomselect top "name N9 C8 ..."]
set sel2 [atomselect top "name ..."]

set pos1 [measure center $sel1 weight mass]
set pos2 [measure center $sel2 weight mass]

set dr [vecsub $pos2 $pos1]
set distance [veclength $dr]

puts "Distance: $distance"

On Sep 26, 2014, at 7:59 AM, amirhossein taghavi <amirhosseintaghavi240_at_REMOVE_yahoo.com> wrote:

> Hello,
>
> May I ask if it is possible to select a group of atoms in DNAlike {N9,C8,N7,C5,C6,N3,C4} and {........another group} and measure the distance between them.based on the center of mass.
>
> Thanks