Hi Nick,

> I tried with a 20" dia circle and it made 60 points
> (did Moi decide how many points)?

What happens there is a circle is what is called a "rational" curve (that's what gives the R in NURBS), which means in addition to x,y,z values for control points there is also a weight value for each control point as well. These weight values are what allow a NURBS curve to exactly represent conic sections like a circle or ellipse.

The AI format does not have any ability in it to have weight values, it can only contain "non-rational" bezier curves in it.

So if you have a rational curve, when you export to AI format it will get refit into a non-rational spline using a tolerance based refinement mechanism.

- Michael