The idea is to define just one polyhedron for the whole model otherwise the union will be lengthy.

Here some example code for inspiration. I used only two polygons. To get a better and smoother tesselation of the winding plancs (and less problems with self-intersections), the trajectory should be described with a more resonable number of polygons. > use > <Naca_sweep.scad> > // http://www.thingiverse.com/thing:900137 > > start = vec3D(gendat_2D(L=100)); // starting shape > end = Rz_(-70, // in this specific case better work with negative angle > to avoid self-intersection > Tz_(90, // translate > vec3D(gendat_2D(L=200)))); > trajectory = [end, start]; > sweep(trajectory); // extrusion, check results with F5/F12, no purple > allowed > > // generate 2D shape of N planks to be extruded > function gendat_2D(N = 20, L=100, D=3, d=1, r=1) = > let(l = L/N, one=[[0, d/2], [r/2, d/2], [r, D/2],[l-r/2, D/2], [l, > d/2]]) > concat ([for(i=[0:N-1], j=[0:len(one)-1]) [one[j][0]+l*i, -one[j][1]]], > [for(i=[N-1:-1:0], j=[len(one)-1:-1:0]) [one[j][0]+l*i, > one[j][1]]]); -- View this message in context: http://forum.openscad.org/alternative-to-hull-tp20461p20481.html Sent from the OpenSCAD mailing list archive at Nabble.com.