Flex is accompanied by ffe (flex front end), a program that connects to flex over a socket and allows more precise user control of the displayed molecule.
Flex is freely available by anonymous FTP at ftp.sdsc.edu in the directory /pub/ccms/flex. The README file in that directory contains most if not all of the information you will need. If you have other questions or comments, send e-mail to ccms-help at sdsc dot edu ,or if you have a WWW client that supports forms (e.g. Mosaic 2.0), you may submit comments through the forms interface
Flex is capable of animating sequences of PDB data. Here are some sample animations that were converted to MPEG format by Jeff Mandell.
This simulation of a small protein molecule was made using Biosym's 'Discover' molecular dynamics program running on a Cray-XMP. Note how the ringed-sidechains approach and withdraw from each other over the course of the simulation.