Orientation style and mirror image transformations

[James W. <ja...@fr...>]

Let's say you have a TriMesh that is subject to an orientation-reversing 
transformation (mirror image).  If you use a backface culling style, 
then the wrong side will be culled, and even if you don't, the geometry 
will look weird due to the vertex normals being reversed.  However, you 
can compensate by introducing a clockwise orientation style.

With the higher-level geometries like Cylinder, this doesn't work, 
because they have a built-in counterclockwise orientation style.  This 
was done in 2003 by Dair Grant, in accordance with QD3D documentation on 
orientation styles, but it seems problematic to me.  Comments?
-- 
   James W. Walker, Innoventive Software LLC
   <http://www.frameforge3d.com/>