Like said, export directly from Sketchup as a stl. Fix it with 3d Builder that is part of Windows10, recheck in Netfabb if all holes are closed and scale it in Meshlab >Filters>NormalsCurvatures Orientation>Transform Scale Been doing it this way for a long time and maybe cumbersome, but it works for me. There are also beautiful plugins for Sketchup such as rounded corners and draw and extrude on curved surfaces. I still use the 2014 version and you get prompted to install a new version all the time, but then you need to reinstall all the plugins.