NOTE: The PhysX plug-in for Max is now maintained by Markus Storm from AGEIA. The official site is now http://physxplugin.sourceforge.net. This page will soon be replaced by a direct link to the official site. 

The PhysX plugin for 3ds max allows artists and developers to author and interactively manipulate complex physical assets including rigid bodies and constraints. The plugin was originally developed by Ageia's Stan Melax, with contributions from James Dolan and John Ratcliff and bug fixes by Feeling Software. It is available for free, along with its documentation below.

AGEIA's PhysX is a Physics engine designed for high performance games and applications, as demonstrated by the large number of game studios who adopted it for their next gen titles. The PhysX plugin for 3ds max exposes the power and performance of AGEIA's PhysX engine in Max. The Max content can also be exported through NxuStream2 to NxuStream's XML format or to COLLADA.

This version covers rigid body dynamics and cloth, including rigid constraints and rag dolls.

Downloads 

NOTE: Make sure to install the PhysX runtime 2.4.4 prior to installing this plug-in.

Download the PhysX plugin for 3ds max 6/7/8

Download the PhysX plugin for 3ds max 9

Documentation

Source code