CAT (Character Animation Toolkit) is a character-animation plug-in for 3ds Max.
CAT is not exposed in the public 3ds Max SDK. However, the source for CAT is included in the 3ds Max SDK Samples under maxsdk\samples\CAT, and can be modified and re-compiled as needed. The CAT source is provided "as-is" and may contain defects. Be aware that CAT is a legacy project. The CAT source is not intended as an example of how to create modern 3ds Max plug-ins.
These topics provide an overview of the structure of the CAT SDK for those who wish to modify it.
The CAT project consists of three directories: