From: Josh Vermaas (
Date: Wed Feb 12 2014 - 17:16:06 CST

Hi Jacob,

Any of the fields that VMD stores as an integer are good candidates for
using the modulo operation on when constructing an atom selection.

residue % 3 == 0 would give you every third residue
index % 2 == 0 would give you every other atom (by index).

You might be interested in more atomselection math functions to limit
the amount of volume that is shown at once.
See for a
simple example.

-Josh Vermaas

On 02/12/2014 02:37 PM, Jacob Durrant wrote:
> A few months ago I was visiting Klaus Schulten's group, and one of the
> VMD developers there showed me a very convenient atom selection for
> selecting every other atom, or every third atom, etc. It made viewing
> large structures much faster and easier. I've searched the internet
> and can't find that command anywhere. Can anyone here point me in the
> right direction?
> Thanks,
> Jacob