Do you get PDF files with CAD drawings inside?
Now you can extract these drawings and save it as DXF file and open it in you CAD application. PDF 2 DXF can open PDF files and save all vector objects as DXF file.
Version 2.0 can now also convert text objects!
Version 3.0 can also recognize lines in pictures and export the lines as dxf file. So you can even process scanned pdf files.
Version 4.0 has a function to vectorize all text objects. It can convert the complete page into a picture and then recognize the lines in this picture. And it can recognize lines in very large pictures in full resolution.