Hi, I am probably trying the wrong way to make a cross section. In general, I do: difference(){ union(){ module1(); module2(); ..... ..... modulen(); } rotate([200,0,0]) rotate([0,90,0]) linear_extrude(height=70,center=false,convexity=10) polygon([[0,0],[50,20],[-50,20],[0,0]]); } The problem is that when I open the .scad file in FreeCad to create a 2D b&w drawing, FreeCad puts the back-side view of cutting wedge and the modules also on the page and from there on the whole thing is FUBARed. See the light gray big triangle and circles on the attached picture. OpenSCAD does not do it. So it is obviously a FreeCad issue, but it might be an issue because I am doing the cross section wrongly. I am looking forward to any hint that shows me the right way, so I can do my little project. Thanks ahead, Infocean <http://forum.openscad.org/file/t3166/Screen_Shot_2021-04-19_at_12.png> -- Sent from: http://forum.openscad.org/