A plug-in is a feature or functionality supplied by an independent program or component. Plug-ins can be supplied by third-party
vendors or independent software developers.
For example, several Video Post filter and layering plug-ins ship with 3ds Max.
The open architecture provides an API (application programming interface) designed to make it easy for other companies to
write plug-ins that extend the core functionality of 3ds Max. See Plug-In Manager.