Are there libraries to assist in AutoCAD structure extraction?

I need to query AutoCAD models to extract structures and connections (e.g., power, data) between them, for storage in a database. I know from experience and research that handling native AutoCAD .dwg is problematic due to the proprietary nature of the format. I see that AutoCAD features a .NET API, but still the problem looks daunting since I have essentially no knowledge a priori of the content of the models. The problem seems like a PhD thesis, as my initial googling hasn't yielded much in the way of tools support or examples.

Are there tools / libraries / examples available to help make AutoCAD extraction feasible in a compressed schedule on a small budget开发者_JAVA百科?

I have essentially no knowledge a priori of the content of the models.

The library is not your problem. Your problem is how the data is modelled, or isn't modelled. You may need to cater for a range of things from attributed blocks to seemingly-unrelated, random bits of text scattered in the proximity of the items in question. If there is no standard for the way this information is stored in the drawing then there is no standard way of machine-reading it. It will probably take longer than a PHD thesis to extract it. You cannot guarantee any sort of comprehensive accuracy either.

AutoCAD (full version, not LT) has Data Extraction routine to extract blocks and attributes from a drawing. If that is how the data is presented then you might be in luck.

It might be cheaper and quicker to hire a team of Muppets to go through the drawings and type the data into something like Excel. You'd be (un)surprised how widespread this sort of practise is, even these days.

As for an inexpensive library, try the Open Design alliance, as mentioned in other AutoCAD questions on this site.