FDO, Feature Data Objects, have been around for almost 7 years. It enables products such as MapGuide, AutoCAD Map, Maestro, Autodesk Infrastructure Map Server, etc connect seamlessly to many standard GIS formats including SQL Server, ArcSDE, and Oracle.
Before there was FDO, AutoCAD Map had a system that was called OSE (Oracle Spatial Extension). This OSE enabled the AutoCAD Map user to seamlessly store Blocks, Lines, Polylines, Points with Object Data, Block Attributes, and Link Templates directly into an Oracle Database and read/write back and forth back into AutoCAD with a click of a button. Seriously.
It was truly seamless CAD/GIS integration.
It still is.
OSE still works in AutoCAD Map 2012 (for now but only on 32bit – blah!).
What FDO/AutoCAD Map needs is to cowboy up. The AutoCAD community needs this to happen to be integrated with Geospatial.
What did OSE do so well? You can map the features in AutoCAD directly to columns in the database. For example, if you drew a Block in AutoCAD and scaled and rotated it, it would dynamicly store those properties in the Oracle database so that when you asked for those BLOCKS again, you got them back in AutoCAD, as BLOCKS (shocker!).
This is true CAD-Geospatial integration. If you have to use Bulk Copy or Safe Software FME, it’s not INTEGRATION.
How would this occur? The FDO datastore (such as SDF, Oracle, SQL Server, ArcSDE, SHP, etc) would have to have some CAD/FDO mapping information for AutoCAD. So when the AutoCAD draftsperson draws a polyline with attached Object Data, it can be stored seamlessly into the SQL Server database and retrieved exactly as is back into AutoCAD.
NO BULK COPY.
Just read/write.

If I spent my days drafting, I would not want to have to learn a new software after years of working with AutoCAD. Read/Write is simple enough.
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