Sweep2rail sees vertical line not maintain same height gap at its top and upper rail

simple profile, initially I tried it as one closed profile but the 2mm radius arc didnt stay as such at the ‘shallow’ end, even after maintain height, it still sees the arc squished.
So I swept that separate and it went twisted, so used roadlike options until it behaved.

then the simple act of sweeping the vertical outer wall, but it ends up sticking up past my arc.

maintain height makes no difference.

is it possible to take the closed profile and sweep it maintaining wall thickness AND the upper arc radius ?

Also how do I do the outer wall separate and have it not go higher then the arc surface ?
sweep2rail defeating me.3dm (190.5 KB)


Ok just a couple of thoughts, not sure they will work. Sweep one rail and then trim off the other side with a surface created from the other rail.
I have found that when I create a complex handrail I need to add in a number of cross sections to help “show” Rhino what it is that I am wanting. i would add those cross section near the turns of the rail. And the cross sections need to be oriented correctly as well. Good luck.


Here’s one way to do this - Extrude the green curve, trim the result with red, OffsetSrf to get the inner faces and then run the arc around the top - Sweep1 on the red curve.
sweep2rail defeating me_PG.3dm (196.3 KB)


(response just prior Pascal 2nd post)
I swept the arc first using sweep1rail, then dupEdge its two edges and used each as the upper rail for each wall using just the line, must work !!!
join all surfaces up,

BUT naked edges where that arc edge was used. Join edges using the superglue command .

I have one little one, its a line and a dot, how the heck do I fix that ?


I tried prior to this predicament, using a cutter through the wall but it turned my cutter into part of the wall.
sweep2rail defeating me2.3dm (760.5 KB)