From: John Stone (
Date: Fri May 16 2014 - 14:20:10 CDT

  Sorry for the very slow turnaround on this topic, I have been traveling
all but one week out of the last 6, and there are many items that are still
on my TODO list now that I'm finally back home...

I have a few questions about the use case for this.
Would you rather record the 3-D haptic/tracker position and force
data and be able to associate it with a simulation timestep, or would
it be fine if you were simply able to record a live movie from the VMD
OpenGL window and have VMD write out an .mp4 file of the simulation
for subsequent playback? In either case, why do you prefer one method
vs. the other, what won't the other method let you do. I want to better
understand the goals you have in mind and limitations you feel each approach
has before I commit to anything.

The second approach (live VMD video recording) might be easy to implement as a
side-effect of other work I'm currently doing to enable remote visualization
GPU clusters and large supercomputers, so I want to know if that would have
any value here, but if not, I do want to understand why not.

  John Stone

On Mon, Apr 07, 2014 at 02:23:09AM -0400, Axel Kohlmeyer wrote:
> On Mon, Apr 7, 2014 at 1:45 AM, Tristan Croll <> wrote:
> > Could it be made possible to save the location of a haptic interface pointer
> > and the applied force vector(s) when recording an IMD trajectory for later
> > playback? I think this would be a very useful feature when generating movies
> > to explain an IMD step, since the only solution at present seems to be to
> > capture video of the OpenGL window on-the-fly.
> adding this directly to the recording function is likely difficult,
> since that is only copying coordinate frames and that part of the code
> knows nothing about IMD. but john is the authority on such deep VMD
> internals.
> on the other hand, it might be possible to script this and write the
> tool status to a separate file whenever a new frame is created and
> then later use this information to draw custom graphics objects into a
> VMD movie. both recording and playback would have to use a trace on a
> suitable VMD variable that gets updated whenever a new frame is
> recorded. There are some explanations in the VMD user's guide and
> several plugins use this mechanism to draw extra graphical elements
> into the VMD screen.
> sorry for no specific answer, but perhaps these pointer can already
> help you find a solution.
> cheers,
> axel.
> >
> >
> >
> > Tristan Croll
> >
> > Lecturer
> >
> > Faculty of Health
> >
> > Institute of Health and Biomedical Engineering
> >
> > Queensland University of Technology
> >
> > 60 Musk Ave
> >
> > Kelvin Grove QLD 4059 Australia
> >
> > +61 7 3138 6443
> >
> >
> >
> > This email and its attachments (if any) contain confidential information
> > intended for use by the addressee and may be privileged. We do not waive
> > any confidentiality, privilege or copyright associated with the email or the
> > attachments. If you are not the intended addressee, you must not use,
> > transmit, disclose or copy the email or any attachments. If you receive
> > this email by mistake, please notify the sender immediately and delete the
> > original email.
> >
> >
> >
> >
> --
> Dr. Axel Kohlmeyer
> College of Science & Technology, Temple University, Philadelphia PA, USA
> International Centre for Theoretical Physics, Trieste. Italy.

NIH Center for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801           Phone: 217-244-3349