Help Modeling Sweep Along Curves

[Dane_Sosna]

Hi,

I was trying to create a 3d revolved/swept object from the curves in this image. I’ve also attached a file. I feel like there is a command to do what I want, but I can’t seem to find it. I want to use two profile curves and sweep the circle along them, tapering to a point. I tried modeling in a small circle at the end to sweep between, as if it were some sort of mishappen cylinder, but I still get strange results. Any help is greatly appreciated.

Sweep Shape Help.3dm (5.7 MB)

[Dane_Sosna]

I figured out what was causing the problem. My two rail curves were tangent to the xy plane at the bottom. I wanted this so that It would be able to perfectly tangentially flow into the ground around it. If I bump up the inner control points every so slightly to make the curves no longer tangent to the xy plane it sweeps just fine. Is there some work around for this behavior? Here is a short video of it.

[leopoldomonzani]

[leopoldomonzani]

Without the final point.