We don’t yet have a 3D offset function, so shells must be made through creative use of minkowski. This will be very very slow, but here’s a starting point (based on the 3D morphology at https://github.com/openscad/scad-utils/blob/master/morphology.scad): module outset(d) { minkowski() { sphere(d); children(); } } module inset(d) { inverse() outset(d) inverse() children(); } module shell(d) { difference() { children(); inset(d) children(); } } module inverse() { difference() { cube(100,center=true); children(); } } shell(2) cube(10); -Marius -- View this message in context: http://forum.openscad.org/Looking-for-advice-tp11305p11307.html Sent from the OpenSCAD mailing list archive at Nabble.com.