Hi Francesco,
An MD Movie "metafile" can be opened with File... Open or the command "open."  It is a simple text file that has the same things you would normally enter into the MD Movie input dialog, for example:

amber 500 1000
prmtop
mdcrd

... if my AMBER input files are named prmtop and mdcrd, and I want to view only frames 500-1000.  The reasoning is that most trajectory formats require more than one file and/or some other parameters to be entered.  Also, in the case of a single PDB file (with MODEL/ENDMDL around each frame), the behavior is different if you open it as a trajectory (allows play-through) than if you just opened it as a regular PDB file (shows all frames together at the same time).

<http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/filetypes.html#molstruct>
<http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/movie/movie.html#metafile>

Maybe this metafile approach will be helpful.
Elaine
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Elaine C. Meng, Ph.D.                       
UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab
Department of Pharmaceutical Chemistry
University of California, San Francisco


On Sep 28, 2010, at 5:47 AM, Francesco Oteri wrote:

PS: Is it possible to add the possibility to open topology directly from the menu File->Open?