In AutoCAD Architecture 2013 the generated Sections/Elevations are incorrect by default.
This behavior is as follows. The generated Elevations and Sections are completely wireframe. Each object can be seen. Hidden is not made to eliminate the hidden objects.
I met this problem in June, 2012, and I found the error correction for it, which can be downloaded from the next link:
usa.autodesk.com > Home > Services & Support > AutoCAD Architecture Services & Support
Downloadable package contains two files, which you have to copy in the root library of the program named AutoCAD 2013. You can find AutoCAD, ACA and MEP here, copy it only in one place, or override the existing ones.
After restarting the program, the Elevation/Section generation will work correctly. If you have already generated one, it is enough to Refresh it.