You're both right.
"Perfect" ray-traced stereo pictures are impossible in PyMOL
because the built-in ray tracer is limited to an orthographic
projection. Unfortunately, I optimized all the vector code for this, so
we're talking a major rewrite to change that : (.
Rotating by a small angle is the best it can currently do unless
you send the geometries to an outside rendering package, such as PovRay.
Warren
--
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Warren L. DeLano, Ph.D.
Principal Scientist
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Voice (650)-346-1154
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-----Original Message-----
From: jparrish [mailto:jparr...@ualberta.ca]
Sent: Wednesday, June 04, 2003 10:34 AM
To: Warren L. DeLano; Tim F
Cc: pymol-users@lists.sourceforge.net; Claudine Mayer; Flip Hoedemaeker
Subject: RE: [ccp4bb]: Pymol stereo question
>> ray angle=-3
>> png image1.png
>> ray angle=3
>> png image2.png
>>
>
>This method of generating stereo images is correct, but also leads to
>quite a bit of vertical parallax (the so-called "toe-in" projection) -
>this is why many stereoscopic images are hard to view properly
(usually,
>edges of the image are out of focus). What you really want is a
>non-symmetric camera frustrum (dunno how hard this is to do in
pymol....)
>where the two images should look along parallel vectors separated by
some
>distance (something like 1/20 the focal length). Check out Paul
Bourke's
>page for all the details:
>
>http://astronomy.swin.edu.au/~pbourke/stereographics/
>
>Hope this helps.
>
> Regards,
> Tim F
I believe this would only be true for perspective projections, not
orthographic, since there is no real "eye" position in orthographic
projections (which are more common in molecular diagrams). Of course,
feel
free to correct me if I am wrong :)
Jonathan
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Jonathan Parrish ph(780)-492-8249
Alberta Synchrotron Institute University of Alberta
Edmonton, Alberta, Canada T6G 2E1
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"Trusting to escape scrutiny by fixing the public gaze
upon the exceeding brightness of military glory, that
attractive rainbow that rises in showers of blood -
that serpent's eye, that charms to destroy, he plunged
into war." -Abraham Lincoln
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