From: Tim Meyer (tim_at_mmb.pcb.ub.es)
Date: Thu Jun 21 2007 - 09:35:40 CDT

dear all,
there have been some similar mails around however i'm still not capable
to get vmd do what i want:(

in one sentence: i want to do exactly what the interactive mouse-center
+ mouse pick_atom sequence does but in tcl.

i want to set the center_matrix and in a way that later scaling zooms
towards the picked atom and not towards origin and later rotation
rotates about the picked atom instead origin.

so of what i understood the center_matrix should look like

>set mat {
  { 1 0 0 $x}
  { 0 1 0 $y}
  { 0 0 1 $z}
}

where x,y,z are the coordinates of my picked atom.

however when i set the center matrix

>molinfo top set center_matrix [list $mat]

this moves the whole molecule until my atom is in the origin. however i
dont want any translation! so when i do the centering by mouse the
global_matrix and rotate_matrix are automatically recalculated to
compensate for the center_matrix

how can i calculate the new global_matrix and rotate_matrix in tcl?

this is for movie making so i'd like to zoom onto a specific atom,
rotate around it and return to the initial view!

if there is a smarter way to attack this problem please let me know

thank in advance

tim