I have got problem with Lathe Extrude + Enviroment Reflection (FresnelER too): http://carmodelviewer.hostoi.com/ring/RingMaterialTestWeb.html
At the end and start of the lathe there is a “line” in reflection.
Another demo pics: http://i42.tinypic.com/2yk0r3c.png
I think this is some kind of issue of the normals (UVs seens good)
Any idea, or workaround?