character studio uses a variety of file formats to save, load, and edit motion.
The BIP file format saves biped motion in general, and the STP file saves footstep patterns only. There are also files that save Motion Flow and Motion Mixer data, and a number of file formats for working with motion-capture data. For a detailed list of these formats, see character studio File Formats.
The file dialogs for Biped motion files include a history list that lets you quickly choose directories where you have recently saved or opened files. 3ds Max maintains a separate history list for each type of motion file.