@bep said:
Yes it is a so-cold sloppy Cad drawing.
Use the plugin "flatten to plane" to get all geometry flat on the working plane.
Use "edge tools" plugin to find and repair as many as possible small errors.
Use the "make faces" plugin to make faces.
Use the plugin "Cleanup" to get rid of all useless geometry.
I would add do some manual clean up either before or upon import of CAD, you don't need some edges (crossing over multiple surfaces, not ending on another edge etc. ) that do not really represent or delineate 3d shapes and appear to be remnants of 2d drawing. Do this before you try to make faces.