From: Axel Kohlmeyer (
Date: Tue Jul 14 2015 - 11:21:27 CDT

On Tue, Jul 14, 2015 at 12:07 PM, Christian Leitold
<> wrote:
> Hello,
> I have recently downloaded VMD 1.9.2 and compiled it from source, as I would
> like to make a slight modification to its XYZ reader. In particular, right
> now the comment line in each XYZ file / frame is not used ("comment lines
> aren't supported by the current version of this plugin."), see:
> Now, I would like to change that, in order to be able to use information
> about the geometry of the simulation box stored in the comment line. As a
> first quick and dirty fix, it would suffice to simply write each comment
> line from a multi-frame XYZ trajectory file to some temporary helper file.
> Unfortunately, I could not get my new version of the plugin to work with
> VMD. The source file is located under
> plugins/molfile_plugin/src/xyzplugin.c,
> and I can compile the plugins without any problems, so that a *.so library
> file is created. However, whatever I do, VMD seems to ignore any changes to
> the plugin. It _seems_ that even if I remove the original from
> VMD's global plugin directory, VMD can still read XYZ files and apparently
> uses the original version. I would really appreciate any hint how to ensure
> my new plugin gets used by VMD.

two things:

- you have to increase the (minor) version number of the plugin (this
is how VMD checks whether it should bother to replace a plugin)
- you may not be able to load files directly from the command line
(file loading is initiated early in the startup sequence and then you
may only have the linked in plugin available, but not yet have the
plugin manager load external plugins).


> Kind regards and thanks in advance,
> Christian

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