VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Fri Sep 03 2010 - 10:08:34 CDT

Bogdan,
  You might try using a quaternion approach (converting from matrix
to quaternion and back):
  http://web.archive.org/web/20041029003853/http://www.j3d.org/matrix_faq/matrfaq_latest.html#Q55

Cheers,
  John Stone
  vmd_at_ks.uiuc.edu

On Fri, Sep 03, 2010 at 12:50:40PM +0200, Bogdan Costescu wrote:
> Hi!
>
> I'm trying to do some animations that require rotations of single
> structures (=no trajectories). Normally I would use 'rotate' to bring
> the orientation from the original viewpoint to the desired one.
> However I want to align the structure in a particular way with respect
> to the viewer, so I use something like:
>
> set M [transvecinv $vector]
> molinfo 0 set rotate_matrix [list $M]
>
> which gives me the desired viewpoint. The original viewpoint is either
> the one VMD sets automatically after loading the structure or a
> previous one obtained through the above procedure. But I haven't found
> a way to compute the intermediate rotations needed for the animation.
> Is there a "matrix way" of doing it or does one have to peek in $M ?
> Either way, if someone has done this already, I would appreciate some
> guidance or even better some code.
>
> Cheers,
> Bogdan 

-- 
NIH Resource for Macromolecular Modeling and Bioinformatics
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