ETO_IKMparse is a library for parsing Autodesk Inventor Engineer-to-Order IKM files. It uses the Antlr parser generator library. It's useful for rewriting parts of an IKM file. See the tests project for an example of how to use it. It's been tested on a few files but probably still has some bugs.
MIT license - http://www.opensource.org/licenses/mit-license.php