Almost all plug-ins require a class ID that uniquely identifies the plug-in. A unique class ID can be generated using a program supplied with the 3ds Max SDK gencid.exe. The following screen capture shows the dialog that gencid.exe presents.

If an object is declared and used by a plug-in and inherits from Animatable it must also have a Class ID.

To obtain a unique Class ID, run the 3ds Max class ID generator program, gencid.exe, located in your \maxsdk\help\ directory. This program generates Class_ID values that are highly likely to be unique.