First of all... there is a Python script that comes with Poser to compress or uncompress all files in a library; they are called "compress files" and "uncompress files"... Second, it's conmpressed using zlib. So you can open a compressed file with Winzip. It's very long, because you must do it for each files. Finally, if you need... i'm developing an application to manage the files in runtimes... I could add the features.