Surface isocurve lines and arcs vs ellipses and splines

I have attached a sample file.
ManVsAuto.3dm (172.5 KB)

But the jist of it is by running a sweep between a diameter and a rectangle. Rhino produces splines and ellipses. By manually breaking down the diameter and splitting in parallel to the radii on the rectangle. The surface iso curves that are produces are proper lines and arcs surface isocurves.

My question is how do i go about getting the cleanest lines and arcs surface isocurves without getting any ellipses and splines in my surfaces. Is there a simpler way than the manual intervention i’ve come up with? The cad program i’m bringing this in to for pathing can read them. But generally causes a ton of fits and sometimes has to be refit in the basic cad program itself before running any kind of pathing.

Thanks so much in advance for any ideas and / or direction i can take here!

Joe

well not so easy…

first your circle is rotated, i am not sure if that will do much difference, sweeping does not quite do the trick here i have no idea why it seems to try to merge surface since they are “too” tangent

what works though is splitting the circle with the segments you have layed out then use ConvertToBeziers join and loft (since all sweep curves are straight and go along the surface tangency). this will produce this exact result you are after though.

Thank you for taking a look and noticing my circle was not perpendicular to the rectangle. Not sure why Rhino did this. Regardless. I’ll give your way a shot and see if this could suit my needs. I’m not familiar with that command so some research in to it will be needed.