DWG Deciphered?
What I've got is the source for my own library which reads DWG files using the
familiar ADS function interface. I've used it to develop a standalone DXF
translator and am working towards a windows viewer. My guess is that Autodesk
will eventually provide an external API but will not document the DWG file
itself. As Jonathan mentioned, it can get "quite hairy" and, IMHO, would be a
nightmare to support.
I would be quite interested in seeing my code put to good use and hope that I
may be able to help you out in some way.
-Chuck