This is a little late, but... I'm trying something similar. Connecting Inventor models to an OPC server to actually watch armatures move. I'm assuming this entails A: building what interface I need of an OPC client, and B: figuring out the API enough to manipulate the constraints and animation functions.
Incredibly new to AutoDesk. Looking for any direction to go so I don't have to reinvent the wheel (should it already be invented for me in part)