Surface extrude revolves around rail. How to extrude surface correctly?

Rhino Rhino for Windows
1

I used a Gumball+Alt to copy a surface end from my stair half-round. I now want to extrude the surface along the curve/rail. (I know how to extrude a curve on a rail, but was looking at other methods) The attached pic is the result I get. what am I doing wrong?

2

Hi CalypsoArt - use Sweep1 here.

-Pascal

3

When I use sweep1 I get the error “Unable to order shapes on rails.”

4

Probably the profile is not joined into a single curve.

-Pascal

5

try DupBorder on the surface then sweep the resulting curve
?

(then Cap)

6

This is a good command to know. It worked for me.