From: John Stone (
Date: Wed Feb 01 2012 - 23:18:23 CST

  You can either save and restore the view matrices (see the ViewChangeRender
plugin source code, or the VMD saved state script source code) and restore
them as-needed, or you could set them to arbitrary matrices of your own
choosing. The "screen units" used in VMD are related to an automatic
scaling factor that is applied such that the "top" molecule fits within
the display window, or in the case of a VR display system like the CAVE,
it is defined such that the molecule is contained within the 3-D "room"
defined by the 4 or 6 walls of the VR display system. If you have more
questions, I can give you assistance in using the VMD display and camera
manipulation commands for whatever it is that you're working on.
I've just been busy getting the VMD 1.9.1 release ready, so thus the
reason I'm a little behind on emails.

  John Stone

On Mon, Jan 09, 2012 at 06:09:46AM -0800, Arham Amouie wrote:
> Hello,
> As far as I know, for every new molecule added, VMD will change camera
> position and scale, so that the whole molecule can be seen. I would like
> to write a script which resets the camera position and scale value to some
> defined absolute values. I guess "translate to" and "rotate" and "scale
> to" are good candidate commands for doing this task. Unfortunately VMD
> User's Guide doesn't explain these commands well (In fact it does not
> explain camera issues clearly). For instance, it explains "translate to"
> command in this way: "Translate to the absolute position (x, y, z) in
> screen units." But what is the definition of screen units? translating to
> a absolute position? Any help will be appreciated.
> Best,
> Arham Amouei

NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801           Phone: 217-244-3349       Fax: 217-244-6078