>>>>>Maybe I still don't quite understand what the main purpose is - it kind of sounded to me like Gaston wanted to get a 4-axis type cut with CAM software that is only currently set up to do 3 axis stuff...
>>>>

Thats basically it, I believe too. Most software under $10,000.00 doesnt do "true 4th axis". It does whats called "indexing" (just rotating the rotary by a provided value at some given point) or "wrapping", where they take one of the x or y values and convert it to an "a" (rotary) value. conversion axis*(360/(2*pi))/radius. The software does this conversion but in "2d". So drawing a circle that needs to be wrapped on a round bar is actually an ellipse.

to cut a 3d model, he needs to read his surface in 2d. I was kindof trying to answer him also with the previous post. The method he used to unwrap the model was cool but didnt take into account the "stretch" that happens with the conversion.

Anyway, thanks.