Your wavy curve doesnt stick out much over the smooth curve. So I scaled the smooth body by scale([.9,.9,1]) If you can cut your curve into concave sections, you can just chain-hull while rotating around the z axis, scaling the wave curve while you rotate around. 2015-09-07 19:22 GMT+02:00 runsun <runsun@gmail.com>: > Hi Neon, it seems that your problem can be approached with simple > interpolation, based on the observation that each line segment between two > points is, or nearly is, a straight line. > > The following is the smooth_points[25] to [26] of your data (blue). Just > increase the y by dy (set to 2.35 here) repeatedly (red horizontal lines), > see if it gets larger than any given smooth_points[i].y. If yes, calc the > slope between smooth_points[i] and [j] (green). The interpolated point at > that y can thus be obtained (I250, I251 and I261). > > <http://forum.openscad.org/file/n13729/interpolation_1597_Neon22.png> > > Here are the functions that generate the I250, I251 and I261 in the above > graph: > > > > function slope(pts,i)= > > (pts[i+1][1]-pts[i][1] ) / (pts[i+1][0]-pts[i][0] ); > > > > function interpolate( pts, i, y=begY )= > > let( slope= slope( pts, i ) ) > > [ pts[i][0]+ (y-pts[i][1])/slope, y ]; > > > > I250= interpolate( smooth_points, 25); > > I251= interpolate( smooth_points, 25, y=begY+dy); > > I260= interpolate( smooth_points, 26, y=begY+dy*2); > > This is to answer your question in the first post. To reach your final > destination, more manipulations are needed. But lets see how you will take > it from here. > > > > ----- > > $ Runsun Pan, PhD > > $ -- libs: doctest , faces ( git ), offliner ( git ); > > tips: hash( 1 , 2 ), sweep , var > > $ -- Linux Mint 17.1 Rebecca x64 + OpenSCAD 2015.03.15/2015.04.01.nightly > > > > > -- > View this message in context: > http://forum.openscad.org/evenly-cutting-two-curves-to-make-surfaces-tp13702p13729.html > Sent from the OpenSCAD mailing list archive at Nabble.com. > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > -- stempeldergeschichte@googlemail.com <karsten@rohrbach.de> P.S. Falls meine E-Mail kürzer ausfällt als Dir angenehm ist: Ich probiere gerade aus kurze Antworten statt gar keine Antworten zu schreiben. Wenn Du gerne mehr lesen möchtest, dann lass es mich bitte wissen. P.S. In case my e-mail is shorter than you enjoy: I am currently trying short replies instead of no replies at all. Please let me know, if you like to read more. Enjoy!

@runsun thanks I'll have a go at that. Should work providing the assumption is made that the segments are all approx the same length (in curviest curve). @PeterFalke Yes several possible ways of making this specific object but this object is arbitrary example and the initial question is about sampling of curves with wildly different samples of knots and how to connect (perhaps using chain hull) them to create surfaces that behave well. Good point though. Thanks. -- View this message in context: http://forum.openscad.org/evenly-cutting-two-curves-to-make-surfaces-tp13702p13742.html Sent from the OpenSCAD mailing list archive at Nabble.com.