Lib3ds is a free toolkit for handling the "3DS" format for 3D model files.  
Its main goal is to simplify the creation of 3DS import and export filters. 

This project is not related in any form to Autodesk Inc. The library is 
based on unofficial information about the 3DS format found on the web. 
 
This  program  is  distributed in  the  hope that it will  be useful,  but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.

The official Lib3ds Homepage can be found under:
  http://lib3ds.sourceforge.net