Posted by  Bob Sprague on February 27, 2001 at 00:51:39:

 
Modeling, DesignWorkshop Professional.   Rendering, Art*lantis.  

Here's an example of creating polyline plans of tubes in PowerCADD and then offsetting the polyline 2 times inwardly.

Polylines imported to DW and then lifted and duplicated to create 6 contours for a 12 sided polygon section
to the tube.

When rendered, the 12 sided polygon clearly gives the effect of being a round tube.

A lot easier than attaching a series of lathed tubes!