From: John Stone (
Date: Sun Feb 05 2012 - 10:44:57 CST

  You can either use an Orthographic projection, or you can reduce the
perspective effect. To reduce the perspective effect, open the display
settings window, and change the "Screen Dist" parameter from -2, to -6
and this will significantly reduce the perspective foreshortening that
you see. You can decrease it even further by changing "Screen Dist" to
-12 or so. As you change the "Screen Dist" parameter, you'll see that
it also has an effect on the field of view, so you'll need to scale or
translate your molecule a little bit if you want the same field of view
you had before moving the camera's center of projection farther back.

  John Stone

On Sun, Feb 05, 2012 at 03:53:57PM -0000, Cosseddu, Salvatore wrote:
> Dear All,
> As a consequence of the perspective view, the spheres (i.g. ions) that
> lies on the borders of the OpenGL display assume a oval shape.
> I can not find a way to avoid this problem, even because the shape is
> maintained once rendered (tachyonInternal, Pov-ray)
> Regards
> Salvatore
> --
> Salvatore Cosseddu
> PhD student
> Centre for Scientific Computing and School of Engineering
> University of Warwick
> Coventry CV4 7AL
> United Kingdom
> email:

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