From: Axel Kohlmeyer (
Date: Mon Apr 07 2014 - 01:23:09 CDT

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

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.


> 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
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Dr. Axel Kohlmeyer
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.