character studio uses several file formats for various purposes.
Biped motion file (.bip). Saves all information about biped motion: the size and scale of the original biped skeleton, footsteps, keyframe data including limb rotation, the active gravity (GravAccel) value, and prop animation. IK Blend values for the keys and Object Space settings are also saved.
You can load the motion saved in a BIP file onto other bipeds with accuracy. See Loading and Saving BIP Animation. You can also use Motion Flow or the Motion Mixer to combine motions saved in various BIP files.
Figure file (.fig). Contains the sizes and poses of each biped body part, and overall biped size. Use this file to save and load a biped pose in Figure mode. See Saving and Loading FIG Files.
Copy file (.cpy). Contains postures, poses, and tracks you have copied using the Copy/Paste rollout. You can load a CPY file created with one biped onto another biped. See Copying and Pasting Postures and Poses and Copying and Pasting Tracks.
Motion Flow Graph file (.mfe). Contains the motion flow graph, and a motion flow script if one was present for the biped when the file was saved. See Saving, Loading, and Appending Motion Flow Graphs.
Motion Mixer file (.mix). Contains clip data, tracks and trackgroups, transitions between clips, track/clip weights, and scale, trim, and time warp information for edited clips. See Mixer Rollout and Exporting Animation to the Biped.
Physique file (.phy). Contains information on envelope sizes and vertex weights set up with the Physique modifier. The data is common to all objects that share this instance of the Physique modifier. You can reload a PHY file, either to restore the data that belong to a particular skin or portion of skin, or to transfer the Physique of one skin (or a portion of it) to a different skin. See Saving and Loading Physique Data.
Step file (.stp). Contains footstep data. Unlike a BIP file, it does not save keys for the feet or the upper body: After you load a STP file, Biped can generate keys based on the footstep pattern. See Loading and Saving STP Files.
STP files are ASCII files; one purpose of this format is to enable developers to write programs that generate STP files.
character studio Marker format (.csm). This is an ASCII (text) format that uses positional markers rather than limb rotation data.
When you import a raw marker file, the positional data is stored in the motion-capture buffer. 3ds Max then uses the marker data to position a biped by calculating limb-rotation data.
Marker Name Map file (.mnm). Not a motion-capture format per se, but a character studio file format that maps custom names in a CSM, BVH, or Importing TRC Files onto the standard list of conventional biped marker names.
(.trc) Can contain both body motion data and facial data. The TRC format is a geometry format that you can import into 3ds Max: See Importing TRC Files for more information. To apply TRC data to a biped, use the MACUtilities utility to convert the TRC format into a CSM file.
The TRC format was developed by the Motion Analysis Corporation.