Ring Band creation script

This OpenSCAD script will generate a plain wedding band style ring.
Most parameters are user selectable such as the ring profile shapes.
This would be ideal as the basis for a wedding ring...

Potentially very useful when combined with the following:
Ring metal cost calculator thingiverse.com/thing:12589
Ring Size System Coversion thingiverse.com/thing:12689
for creating and costing a custom wedding band or other such tomfoolery.

Author: Mark Gaffney
Version: 1.4
Date: 2013-03-19

Todo:
Implement texturing
Implement hallmarking

Warning:
Let the right one in

Changes from previous versions:
1.4

• added ellipse_intersection.scad code for 2 new cross section shapes (cs_ellipse_intersection & cs_rounded_ellipse_intersection)
  

• added support for write.scad on inside or outside of ring, engraved or raised
  

1.3

• Xxxxx's wedding ring version (no stone, no mount)
  

1.2

• Made higher resolution shapes by increasing rotate extrude $fn from 50 to 100 and shape $fn from 20 to 40
  

• Implemented half chamfered rectangle
  

1.1

• Fixed issue whereby rounded rectangle shape CS appeared slightly translated in Y direction
  

• Fixed issue whereby half ellipse was never shown and normal ellipse was shown twice instead
  

1.0

• First version based on Ring_band_creation_script_v0.10.scad
  

• Added more cross sections (cs_half_pill, cs_reverse_hemi_ellipse, cs_reverse_rounded_hemi_ellipse)
  

Ring profiles available:
pill, ellipse, hemi_ellipse, rounded_hemi_ellipse, rectangle, scallopped_rectangle, rounded_scallopped_rectangle, rounded_rectangle, chamfered_rectangle, half_pill, reverse_hemi_ellipse, reverse_rounded_hemi_ellipse