6-Strand tubular braid, in Moi, using Moi Commands that reproduce the instructions of kevinjohn.

http://kevinjohn3d.blogspot.com/2011/06/modeling-tubular-braid-braided-rope-in.html

In Top View, create two 3-sided polygons of radius 25 and 100.
Connect vertices to make the star shape.

Join star shape, Show pts, and offset the vertices in front view, in the z direction,
by 50, 100, 150,...300 units. This can be done by progressively selecting the proper
points and line segments, starting at the leftmost and going counter clockwise.
Some practice was necessary to get the selections right. Join line segments to form
a spline. Do a linear Array of say 3 copies to lengthen the braid, and join
the resulting spline. Note that the points lie on either an inner or larger outer
helix.

A sweep circle, of radius 20, can be aligned with the cplane command.
A Fillet of the spline was done with radius 20. Sweep the circle.

In Top View, Circular Array 3, the swept spline Strand. (Equals two revolve copies
of 120 degrees.) Mirror the 3 strands in Top View. A point at 30 degrees helps.
Move the 3 Mirrored strands up in Front View by 50 units.
Colors may be changed.

The braid was Boolean difference trimmed with two planes, and the center section
moved back to the origin, after deleting the first and third sections of the braid.

Another paper talks of using a "bspline" instead of a sine or cosine lissajous curve,
because it can have a more uniform curvature.

Question for Michael: Is it possible to "disconnect" one vertex of a closed polygon?
(Selecting just one of the adjoining line segments of the joined polygon allowed moving the line with other control point.)

- Brian

ps Have to try the other tutorial, which does flat braids...