Hi Barry,

You wrote : ""I swept circles and used the pipe produced to cut surface.
The cut edge is used to sweep and cut the next edge and so on.""

I wonder what you did with the pipes where the radius of the rail curve
got so narrow that it forced the pipe to buckle ?

Getting a smaller circle for the Sweep wont help as the pipe will buckle
later when moving upward to the top ...

Hi Tom,
in my example I had split you model in two so that didn't happen.
Anyway have just checked and you can get round it.
Create the curves as before and then trim them back with a circle or sphere.
The curves can then be blended and joined.

Barry

Hey dear MOIers,

Currently putting all the input of this thread together I want to thank
everyone who has contributed with his infos, suggestions and ideas.
The MOI community has the same amazing spirit of contribution and
support as the maker of MOI and that is wonderful !