Hi Pirandos,

re:
> But how come that short curve segment appears??? I draw normal curves but after some
> manipulations it brakes in to segments

It's hard to say without being able to reproduce it but it's probably from the same issue that is ending up with some small gaps between surfaces.

If I had the curves available to examine, I would look for places where their endpoints are not all exactly lined up with each other.

- Michael