My new favorite design tool for my laser? #FreeCAD!
Details: I use #K40Whisperer and Inkscape files. But designing things to a specified size can be extremely tedious in #Inkscape. FreeCAD to the rescue! Sketches in FreeCAD can be exported to a “Flattened SVG” file. This works…mediocre with the full models, and has problems with parts that aren’t already laid flat. But, you can export a sketch directly!
If not already in the XY plane (read: flat) then simply copy the desired sketch, paste it into a new file, switch to the Sketcher workbench, then select Sketch->Reorient sketch… and change to the XY plane. Then, with only that sketch selected in the treeview, select File->Export…, and select “Flattened SVG”. Viola! You can now open the file in Inkscape, set the fill/stroke/stroke paint as desired for K40 Whisperer. E.g. 255 red to vector cut, 255 blue to vector engrave, and all 0 (black) to raster engrave. Sweet!