This and more information can easily be extracted from AutoCAD DWG files. The process can be automated and exported into most custom formats based on user requirements. I just did a project like this using the Brep API for .NET that was added to AutoCAD 2009. I used AutoCAD 2010, Visual Studio 2008 and C# for this referencing C:\Program Files\AutoCAD 2010\acdbmgdbrep.dll.
The 3dsolids are composed of Complexes, Shells, Faces, Loops and Edges.