I create the 2d profiles in Draftsight which is free AutoCAD clone (I wish it had lisp capability though). I would prefer to use AutoCAD, but do not have a license for that. I wrote a visual basic program to create the Linear extrude data rather than importing a dxf file into openscad. I just do a list of the polyline data & copy & paste that into the visual basic program. I use turbocad to generate the ledges by extruding along a path as that was the simplest way for me to do that. I probably should spend some time learning more of the features of turbocad as it seems quite powerful for the money. I also use turbocad to generate DWG files from STL files to use in Draftsight.