Dan, Those results are close enough for me too. I will explore your post more later. I laid the curves length out flat as you did and my surfaces curve edge came out in the 20's. Way off.

Since yours came out so close, I will explore and digress to what you've done there.

Thanks for getting back to me.

By pointing out the difference in the Rhino edge and the original, really miniscule, I was just pointing out that it is not an exacting thing, from what I have read and tried to learn on it. Your results are great too. I was assuming since you laid your line straight as did I that your curve would be way off like mine. But NOOOoooo. Mucho gracias for the post!