why can't I get smooth bottom?

 From:  PaQ

If you're talking about the pole pinch (red arrow), I don't get where it comes from.
I'm using the same technique as you, and with the provided curves, and I don't have the problem.

Are you using the same building steps ?

- Select a,b,c profiles
- Sweep
- Select the 1,2 rails
- Pick the red curve as railing scale.

EDITED: 3 Feb 2010 by PAQ