From: Axel Kohlmeyer (
Date: Tue Jun 26 2007 - 16:24:22 CDT

On Tue, 26 Jun 2007, Jana Black wrote:

JB> Axel - thanks for the reply. We have a 16-screen video wall driven by 16
JB> dual processor nodes and I would like to display 16 different
JB> simulations simultaneously using VMD (I'm also looking at using VisIt)
JB> but maintaining the simulations consistent in time (i.e., each display
JB> shows the configurations at the same time). There are several ways I

ok. so what you want to do is some sort of 'inverse IMD', i.e.
you want to remote control multiple VMD sessions (i don't see,
how this could be done with a single session).

as far as i can tell, this has not been done before, but you
have some sort of remote control of VMD sessions in the biocore
plugins. perhaps one can utilize this and hack it to load multiple
different visualizations instead of the same into the various
individual VMD sessions and then use some custom frontend (Tk) GUI
to control/synchronize all sessions.

i could also imagine writing some sort of script that would
load all molecules on top of each other on a (frontend) machine
and then loop over all molecules write the visualization to
disk and have an an external renderer pick up the file and
render and display it on the corresponding screen. that would
be rather slow, though, if you want that to be interactively,
if you just want to show a given movie, you could of course
just render individual (mpeg) movies and then play them in parallel,
but from the elaborate setup i'd expect that you prefer interactive

in short, i'm certain that something can be done, but i'm not
aware of any pre-existing package (who has that kind of facility
available anyways?), so it'll take some scripting effort to
make it work.

hope that helps,

p.s.: i'm cc'ing vmd-l in case other people there have some more
experience (i'm very old fashioned and have not yet been fully
convinced that these special display facilities have significant
value besides being impressive ;-) ).

JB> thought this could be done. One would be, if there was a parallel VMD
JB> that visualized using distributed rendering, I could make a file in
JB> which at each time step I had all sixteen configurations displaced from
JB> each other in the one data file and have VMD do parallel rendering. It
JB> would then push each frame onto the 16 screens, but by judicious choice
JB> I would end up with one simulation in each screen. It looks as though
JB> someone may have done this at the recent Apple WWDC displaying the
JB> result of a simulation of a large protein. The other solution (simpler)
JB> would be to run 16 copies of VMD, one on each processor with each copy
JB> having the data file for its simulation, and then I just need to be able
JB> to trigger the VMDs so as to keep them in step. I don't know if anyone
JB> has done this in the past.
JB> Thanks for any help you can offer.
JB> -Jana
JB> >
JB> > JB>
JB> > JB> Thanks!
JB> > JB> Jana
JB> > JB>
JB> >
JB> >

Axel Kohlmeyer
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
If you make something idiot-proof, the universe creates a better idiot.