Nonius Collect: Crystal Movie experiment

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Making a movie of the crystal

The crystal movie experiment contains some tools for creating an MPEG movie of a crystal with the crystal habitus drawn around it.

Prerequisites

For the crystal movie experiment to work, you need the "ImageMagick" and "ghostscript" packages installed on your system. The "convert" program from the ImageMagick suite is called from the experiment to convert initial PostScript output to a "ppm" format, which can be used by mpeg_encode.

ImageMagick can be found on the Internet at:

http://www.imagemagick.org/

ghostscript can be found on the Internet at:

http://www.cs.wisc.edu/~ghost/

Both of these packages come standard with the RedHat linux system.

To actually build the movie, you must have the "mpeg_encode" program installed on your system. This program can be downloaded from the internet at:

 
http://bmrc.berkeley.edu/frame/research/mpeg/mpeg_encode.html

Functioning

The experiment will pop up a manipulator window like the crystal viewers in the orientation experiment. The crystal can be oriented here using the mouse. Once a good orientation is found, a click on the "Movie" button will make 360 snapshots of the crystal at 360 different positions of the Phi motor.

One auxilliary file will be written, called "xtal.par". Using the command

mpeg_encode xtal.par

The snapshots can then be converted into an MPG movie.

Bugs

On a 200MHz Pentium, it takes up to 2 hours to create the 360 snapshots of the crystal, and up to another hour to create the mpg movie. This is way too long to be practical. If this is considered a useful experiment, we will consider speeding things up.

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