VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Thu Dec 14 2000 - 10:51:17 CST

Hi,
  You are absolutely correct. As far as I know there isn't a way to
specify an orthographic camera in POV-Ray, if there is, we just need to
be made aware of this and we can write code for VMD that will do it.
As far as we currently know though, POV doesn't have an orthographic camera
capability. (We're not POV experts though, so if someone knows a good way
of doing an orthographic camera in POV, we're all ears...)

You can probably "fake" an orthographic camera by moving the camera
position 10 times farther away from the molecule, and then increasing
its "zoom" (or decreasing the size of the image plane) by a factor of
ten. This isn't really an orthographic view, but it significantly
reduces the apparent perspective, using factors larger than 10 reduces
the perspective even further. An orthographic view is basically the same
as a perspective view where the camera is infinitely far away and zoomed
in "infinitely". Most renderers have some sort of limit or beging to lose
numerical precision somewhere on the way to infinity, so the technique doesn't
completely accurately approximate an orthographic view, but its better
than nothing. Factors of 10 and 20 ought to work pretty well without
messing up the numerical precision of most renderers.

If anyone else has suggestions on this, please let us know.

  John Stone
  vmd_at_ks.uiuc.edu

On Thu, Dec 14, 2000 at 05:43:39PM +0100, Siegmar Kardinal wrote:
> Hallo,
>
> Images redered by povray seem allways to be in perspective
> projection wheter ortographic mode is choosen from the Display menu or
> not.
>
> Is there any way to circumwent this?
>
>
> Thanks in advance
>
> Siegmar
> 

-- 
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
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